Parasite Of Cattle Research Articles

Seasonal recovery of Eimeria oocysts from soil on naturally contaminated pastures

Though Eimeria is an important parasite of cattle, research is lacking on how the parasite persist in the pasture soils. In this study, feces samples were collected from three pastures in June and October 2010 and soil samples in April 2011. Coordinates of sampling locations were recorded with Global Positioning System together with information about grass cover, shade, and elevation. All soil samples were collected from the same locations as the fecal samples and used in model evaluating the possible factors influencing the concentration of oocysts in the soil. Feces and soil samples were investigated using a quantitative flotation technique. Eimeria oocysts were found in 95.6% of fecal samples collected in summer and 84.5% of samples in fall. In contrast, the same locations soil samples were positive for Eimeria oocysts in 37.3% (summer) and 44.3% (fall). Despite larger numbers of oocysts in fecal samples shed during summer compared to fall, there was no difference in the concentration of oocysts in soil samples the following spring. The odds of higher numbers of oocysts in soil samples in spring were higher if fecal samples collected in summer were in shade or if containing Eimeria alabamensis during the fall. Factors other than the concentrations of oocysts shed in feces appear to affect whether oocysts persist between grazing seasons.

Unexpected occurrence of Haemonchus placei in cattle in southern Western Australia

Haemonchus placei is an abomasal parasite of cattle, primarily in tropical and subtropical areas of the world. In Australia, this nematode can be extremely pathogenic in summer rainfall areas, particularly in the hot, sub-tropical Kimberley region, in the far north of the state of Western Australia (WA). Although cattle are occasionally transferred to southern parts of WA, it was believed that H. placei did not occur in southern regions of WA, as it is less cold-adapted than Haemonchus contortus, and the free-living stages would not develop during the cold winter and dry summer periods. Here, we show that, although H. contortus is found in cattle in the temperate southern region of WA, it appears that H. placei also occurs in southern WA. While investigating the prevalence of anthelmintic resistance in nematodes of cattle in WA, the existence of H. placei was suspected on a range of participating farms, following the morphological examination of third-stage larvae cultured from faeces, and of adult worms recovered from sheep experimentally infected with these larvae. Genomic DNAs from individual worms as well as eggs from pooled faecal samples from seven farms in southern WA were subjected to PCR-based mutation scanning and sequence analyses of the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA. The results showed that both H. contortus and H. placei were harboured by cattle. This first record of H. placei in cattle in southern WA raises questions as to the prevalence and distribution of this parasite in other temperate and cool climatic regions of Australia. Although clinical disease due to H. placei has not yet been seen in southern WA, global, climatic trends might suggest an increased importance of this parasite in the longer term.

Mutation in the RmβAOR gene is associated with amitraz resistance in the cattle tick Rhipicephalus microplus

We aimed to describe the evolution of resistance to amitraz in Rhipicephalus microplus in the field and to test the association between amitraz resistance and the frequency of a mutation in the β-adrenergic octopamine receptor gene (RmβAOR). We established six populations of Rhipicephalus microplus ticks in similar paddocks by the admixture of ticks from strains known to be susceptible and resistant to amitraz and synthetic pyrethroids. Each population was managed using one of three acaricide treatment regimes: always amitraz, always spinosad, or rotation between amitraz and spinosad. We used microsatellites to elucidate population structure over time, an SNP in the para-sodium channel gene previously demonstrated to confer resistance to synthetic pyrethroids to quantify changes in resistance to synthetic pyrethroids over time, and a nonsynonymous SNP in the RmβAOR, a gene that we proposed to confer resistance to amitraz, to determine whether selection with amitraz increased the frequency of this mutation. The study showed panmixia of the two strains and that selection of ticks with amitraz increased the frequency of the RmβAOR mutation while increasing the prevalence of amitraz-resistance. We conclude that polymorphisms in the RmβAOR gene are likely to confer resistance to amitraz.

Cattle movements and trypanosomes: restocking efforts and the spread of Trypanosoma brucei rhodesiense sleeping sickness in post-conflict Uganda

BackgroundThe northwards spread of acute T. b. rhodesiense sleeping sickness in Uganda has been linked to cattle movements associated with restocking following the end to military conflict in 2006. This study examined the number of cattle traded from T. b. rhodesiense endemic districts, the prevalence of the parasite in cattle being traded and the level of trypanocidal treatment at livestock markets.MethodsBetween 2008 and 2009 interviews were carried out with government veterinarians from 20 districts in Uganda, 18 restocking organisations and numerous livestock traders and veterinarians. Direct observations, a review of movement permit records (2006 to 2008) and blood sampling of cattle (n = 1758) for detection of parasites were also conducted at 10 livestock markets in T. b. rhodesiense endemic districts.ResultsRecords available from 8 out of 47 identified markets showed that 39.5% (5,238/13,267) of the inter-district cattle trade between mid-2006 and mid-2008 involved movement from endemic areas to pathogen-free districts. PCR analysis showed a prevalence of 17.5% T. brucei s.l. (n = 307/1758 [95% CI: 15.7-19.2]) and 1.5% T. b. rhodesiense (n = 26/1758 [95% CI: 0.9-2.0]) from these same markets. In a two-year period, between late-2006 to late-2008, an estimated 72,321 to 86,785 cattle (57, 857 by 18 restocking organisations and 10,214 to 24,679 by private traders) were imported into seven pathogen-free northern districts, including districts that were endemic for T. b. gambiense. Between 281 and 1,302 of these cattle were likely to have carried T. b. rhodesiense. While governmental organisations predominantly adhered to trypanocidal treatment, most Non-Governmental Organisations (NGOs) and private traders did not. Inadequate market infrastructure, poor awareness, the need for payment for drug treatments, and the difficulty in enforcing a policy of treatment at point of sale contributed to non-compliance.ConclusionWith increasing private trade, preventing the spread of Rhodesian sleeping sickness in Uganda requires government support to ensure mandatory trypanocidal treatment at livestock markets, investment in market infrastructure and possible drug subsidy. Mapping the northern reaches of T. b. rhodesiense in livestock and preparation of risk assessments for cattle trading could mitigate future outbreaks.

Nested PCR Detection and Phylogenetic Analysis of <i>Babesia bovis</i> and <i>Babesia bigemina</i> in Cattle from Peri-Urban Localities in Gauteng Province, South Africa

ABSTRACTBabesia bovis and Babesia bigemina are tick-borne hemoparasites causing babesiosis in cattle worldwide. This study was aimed at providing information about the occurrence and geographical distribution of B. bovis and B. bigemina species in cattle from Gauteng province, South Africa. A total of 268 blood samples collected from apparently healthy animals in 14 different peri-urban localities were tested using previously established nested PCR assays for the detection of B. bovis and B. bigemina species-specific genes encoding rhoptry-associated protein 1 (RAP-1) and SpeI-AvaI restriction fragment, respectively. Nested PCR assays revealed that the overall prevalence was 35.5% (95% confidence interval [CI]=± 5.73) and 76.1% (95% CI=± 5.11) for B. bovis and B. bigemina, respectively. PCR results were corroborated by sequencing amplicons of randomly selected samples. The neighbor-joining trees were constructed to study the phylogenetic relationship between B. bovis and B. bigemina sequences of randomly selected isolates. Analysis of phylogram inferred with B. bovis RAP-1 sequences indicated a close relationship between our isolates and GenBank strains. On the other hand, a tree constructed with B. bigemina gp45 sequences revealed a high degree of polymorphism among the B. bigemina isolates investigated in this study. Taken together, the results presented in this work indicate the high incidence of Babesia parasites in cattle from previously uncharacterised peri-urban areas of the Gauteng province. These findings suggest that effective preventative and control measures are essential to curtail the spread of Babesia infections among cattle populations in Gauteng.

Comparison of gastrointestinal parasites and management practices between organic and conventional dairy herds in Minnesota

Clinical infestations with gastrointestinal (GI) parasites are considered by some to be among the most expensive diseases in the cattle industry due to lost productivity and increased operating expenses. The National Organic Program restricts the use of synthetic anthelmintics to emergency situations. Instead, organic farmers are required to implement best management practices and alternative therapies to prevent GI parasite infestations. At present, little is known about the burden of GI parasites in dairy cattle in Minnesota or the effectiveness of preventive management practices on organic dairies. The objectives of this study were to describe the prevalence of GI parasites in cattle on Minnesota dairy herds, to evaluate the association of management practices with GI parasite egg counts, and to compare GI parasite egg counts between organic and conventional dairy farms.

Discovery of the Rdl mutation in association with a cyclodiene resistant population of horn flies, Haematobia irritans (Diptera: Muscidae)

The horn fly, Haematobia irritans irritans, is an obligate blood-feeding parasite of cattle that causes significant economic impact in many countries. We investigated the resistance of a horn fly population from Louisiana/USA to endosulfan, a cyclodiene insecticide. Bioassays were performed in 2010 and 2011 in order to determine the resistance ratio of the population to endosulfan and a PCR assay was developed to detect the Rdl mutation which is the replacement of an alanine with a serine at the GABA receptor locus that has been associated with resistance to cyclodienes in other insect species. Endosulfan tags had provided 8 weeks of effective control in 2010 but only 1 week in 2011. After only one summer (June–September/2010) of exposure to the endosulfan tagged cattle, there was a significant increase in the resistance ratio for endosulfan in the fly population. Most flies surveyed by the PCR diagnostic assay were homozygous susceptible at the Rdl locus, the resistant (R) allele was mainly present in the heterozygous state and there was no difference in the frequency of the R allele between female and male flies. After the first year's exposure of the horn flies to the endosulfan tags, the frequency of the R allele increased significantly. However, after one year without endosulfan treatment (2011–2012), the frequency of the R allele significantly dropped. These results indicate that target site resistance was responsible, at least in part, for the resistance and that a fitness cost is possibly associated with the Rdl mutation.

Concurrent infection and seasonal distribution of gastrointestinal parasites in cross-bred cattle of Sirajganj district in Bangladesh

Aim: To determine the extent of concurrent infection and seasonal distribution of gastrointestinal parasites in cross-bred cattle of Shahzadpur upazila of Sirajganj district, Bangladesh. Materials and Methods: Faecal samples from 4248 cross-bred cattle presented to the diagnostic centre of Milk Vita, Baghabari, Sirajganj with complains of digestive disturbances over the period from November, 2008 to October, 2009 were examined grossly with naked eye followed by microscopic examination with direct smear method, Will's floatation and sedimentation techniques. Results: Out of 4248 faecal samples examined, 3268 (76.93%) samples harboured one or more parasitic ova or cyst and the rest 980 (23.07%) samples found free of parasitic ova or cyst. Among the positive cases, single infection of fascioliasis (29.0.5%), paramphistomiasis (8.3%), toxocariasis (11.32%), haemonchosis (2.47%), monieziasis (0.7%), balantidiasis (4.19%), trichuriasis (1.1%), trichostrongylosis (1.4%) and strongyloidosis (1.6%) were diagnosed. Mixed infection with at least two (dual infection) and/ or any three of above mentioned parasitic species (triple infection) were also recorded. Cattle harbouring eggs of one parasite were more common [60.03% (95% Confidence interval (CI): 58.53, 61.51)] than those harbouring eggs of two [15.44% (95% CI, 14.36, 16.56)] or three [1.46% (95% CI, 1.12, 1.87)] parasites concurrently. Significantly (p 0.05). A non-significant (p>0.005) decreasing trend of occurrence from winter through summer and rainy season was also observed in case of trichostrongylosis. Conclusion: The result of current study clearly indicate that helminth infections are highly prevalent in cross-bred cattle of the study area. The findings on abundance and distribution of gastrointestinal parasitism in different age groups of cattle, the polyparasitism nature of the disease and the seasonal variation of occurrence obtained from present study will therefore assist the clinicians for forecasting of parasitism and make awareness among the farmers to take appropriate control measures against them.

High infestation by Rhipicephalus (Boophilus) microplus in a mare: a rare case report

Rhipicephalus (Boophilus) microplus is a natural parasite of cattle, with rare reports of parasitism in horses. Therefore, the aim of this study is to report a rare case of high infestation by R. (B.) microplus in a mare in the town of Riqueza, state of Santa Catarina, Southern Brazil. In December 2012, in a farm with 12 horses in its herd, a single mare was highly infected, showing clinical signs such as pale to pink mucous membranes and bleeding in the neck, the main place in her body where the ticks were fixed. The horse was treated through the use of a spray with a drug association of cypermethrin, chlorpyrifos, and citronellal (Colosso®), showing temporary effectiveness, since 15 days posttreatment immature forms (larvae and nymphs) of ticks were again found. Therefore, this mare has high susceptibility to parasitism by R. (B.) microplus, differently from the other horses at the same farm that were not parasitized by this mite.

Out of sight but not gone: Sero-surveillance for cattle grubs, Hypoderma spp., in western Canada between 2008 and 2010

Despite the lack of evidence of clinically infected cattle in western Canada since the late 1990s there is persistent evidence from serological sampling that warble fly infections remain endemic. As part of a general survey of cattle parasites conducted on calves entering a feedlot in southern Alberta sera were tested for the presence of anti-Hypoderma antibodies using an established ELISA. Calves for the study were drawn from auction markets in Manitoba, Saskatchewan, Alberta and British Columbia and serum samples were collected, according to a randomization scheme, as the calves entered a single feedlot in October through December (Survey) of three consecutive years (2008–2010). In addition, a sub-sample of calves originating on a ranch in southeastern Alberta (Ranch 1) that had been the subject of previous surveillance was tested. Sero-prevalence of anti-Hypoderma antibodies of the Survey calves ranged from 0.0% to 100.0% depending on origin and overall varied among the three years with the sero-prevalence being 45.6%, 26.9%, 28.5% in 2008, 2009 and 2010 respectively. Sero-prevalence in Ranch 1 calves varied among years, with one year being much higher and was different from overall Survey sero-prevalence in two of three years (31.7%, 64.1%, 38.5% in 2008, 2009, 2010 respectively). In the Survey population there was a trend to lower sero-prevalence over the three years while on Ranch 1 there was no clear trend. In the samples with ELISA adjusted absorbance values above the positive cut-off an examination of the cumulative relative frequency showed that in all years approximately 90% of the samples were in the lower 3 of 14 bins in both populations and in two of three years in Ranch 1 population. The clustering of the positive ELISA data at the lower end of the range is suggestive of low level grub infestations. The increased frequency of high positive ELISA results from Ranch 1 in 2009 potentially indicate an ‘outbreak year’ in which pupal and adult fly survival was higher than for other years of this study resulting in more infested animals with higher burdens. Examination of precipitation and temperature profiles from the subject ranch support this suggestion.

Gastrointestinal nematode infection and performance of weaned stocker calves in response to anthelmintic control strategies

Gastrointestinal nematode (GIN) parasite control recommendations are in a state of flux because of the increase in anthelmintic resistant cattle parasites, such as Cooperia spp. In addition, Cooperia spp. infection is typically high in warm-season grass pastures and can affect growth performance of grazing stocker calves in the Gulf Coast Region. This study evaluated the effects of moxidectin pour-on, oxfendazole oral suspension, or a combination of the two given at separate times on infection and performance of weaned beef calves grazing summer forages. Steers (n=42) and heifers (n=31) were stratified by sex, d-11 fecal egg count (FEC), and d-1 shrunk body weight (BW) to one of 10 pastures with four anthelmintic treatments and one control. Treatments included: (1) oxfendazole given on d 0 and moxidectin on d 73 (O+M), (2) moxidectin given on d 0 and oxfendazole on d 73 (M+O), (3) moxidectin given on d 0 (M), (4) oxfendazole given on d 0 (O) and (5) no anthelmintic given (CON). Calves grazed for d-110 beginning May 27th. Response variables were FEC (collected on d-11, 14, 31, 45, 59, 73, 87 and 108), coprocultures (evaluated for d 87 and 108), final shrunk BW, shrunk BW gain, average daily gain (ADG), and full BW gain (collected on d 31, 59, 73, 87, and 108). Calves treated with either oxfendazole (O+M and O) or moxidectin (M+O and M) on d 0 had significantly lower (P<0.001) FEC than the CON calves on d 14, 31 and 45. However, the M+O treated calves had significantly higher (P<0.001) FEC than both oxfendazole treated groups. In addition, calves treated with a second dewormer on d 73 (O+M and M+O) had significantly lower (P<0.001) FEC by d 87 than the CON or M treated calves. Shrunk BW gain and ADG were significantly greater (P=0.005) for the O+M compared to the M treated and CON calves, but comparable with the M+O and O treated calves, respectively. Coprocultures sampled on d 87 and 108 for calves not receiving a second dewormer were predominantly Cooperia spp. and Ostertagia spp. On d 87, no larvae were recovered from the M+O treated calves, whereas the O+M treated calves had 94% Cooperia spp. and 3% Ostertagia spp. recovered. Providing a benzimidazole with a macrocyclic lactone given at two different periods may provide better GIN parasite control and improve animal gains for stocker calves grazing warm-season grass pastures.

Parasitic stage of Ostertagia ostertagi: A mathematical model for the livestock production region of Argentina

The model here presented describes the dynamics of adult Ostertagia ostertagi parasites in cattle in the field. The model also describes the population of infecting L3 larvae subject to the conditioning process while in the pasture as well as the inhibition–disinhibition process in ingested L4 larvae. The model has two modules: one for the conditioning process and the other for the parasitic stage. The first module determines the proportion of ingested L3 larvae that will go through an arrested stage of development, or hypobiosis, and for how long depending on the weather conditions and the length of the period of exposure in the pasture. The second one describes the adult population dynamics as disinhibiting larvae and recently ingested larvae accumulate in the animal. The model has a discrete daily step and is parameterized using fuzzy inference systems of the Mamdani type (FM). Given that the inhibition–disinhibition process is not yet fully understood, a series of perturbations on the different input variables were performed with the purpose of analysing the model's behavior. Simulations show that the adult population exhibits two maximal peaks of infection in the hosts in December–January (Summer) and April–May (Autumn). These high values are a consequence of hypobiotic larvae resuming their development at those times.

Fowl adenovirus-infecties bij vleeskuikens in België: een overzicht van tien jaar

Tussen mei 2002 en mei 2012 werden bij 38 van 310 zieke Belgische vleeskuikentomen fowl adenovirus (FAdV) infecties gediagnosticeerd. De FAdV-isolaten werden meestal bekomen uit mengstalen van meerdere organen waarin vooral lever, pancreas en bursa aanwezig waren. De FAdV-isolaten behoorden tot de serotypes FAdV 1 (vijf stammen), FAdV 2/11 (dertien stammen), FAdV 3 (één stam), FAdV 5 (acht stammen) en FAdV 8a (vier stammen); zeven isolaten konden niet met zekerheid getypeerd worden. De klinische klachten bij geïnfecteerde groepen bestonden uit groeivertraging, nat strooisel, ademhalingssymptomen en/of manken in respectievelijk 63%, 37%, 26% en 24% van de gevallen. Verhoogde sterfte trad op bij 39% van de tomen. Bij 53% van de geïnfecteerde bedrijven waren de symptomen reeds meerdere productiecycli na elkaar opgetreden. De meest consistent waargenomen letsels waren hepatitis, nefritis, myocarditis, pancreatitis, tracheïtis en proventriculitis. Gelijktijdige infecties met reovirus, infectious bronchitis virus, avian metapneumovirus, infectious bursal disease virus, chicken anemia virus, Escherichia coli, Enterococcus cecorum en/of Eimeria werden waargenomen bij 53% van de tomen, vooral bij de groepen die af te rekenen kregen met verhoogde sterfte. Er werd besloten dat fowl adenovirussen vaak een rol spelen bij ziekte van Belgische vleeskuikens, alleen of in combinatie met andere infectieuze agentia.

Anthelminthicumresistentie van gastro-intestinale rundernematoden

Anthelminthicumresistentie van parasieten bij kleine herkauwers, runderen en paarden wordt wereldwijd steeds groter als gevolg van een overmatig gebruik van de beschikbare ontwormingsproducten. In België is Cooperia oncophora de meest voorkomende rundernematode waarbij resistentie wordt vastgesteld; voorlopig enkel tegen macrocyclische lactonen. Eens resistentie is vastgesteld, kan het nodig zijn om over te schakelen naar een product met een ander werkingsmechanisme. Er zijn echter bijna geen nieuwe doeltreffende ontwormingsproducten meer beschikbaar. Het is daarom belangrijk dat landbouwers en dierenartsen een evenwicht vinden om zowel worminfecties onder controle te krijgen als de duurzaamheid van hun behandelingsstrategie te garanderen. Op deze manier kan de ontwikkeling van anthelminthicumresistentie vertraagd worden en de doeltreffendheid van de beschikbare anthelminthica verlengd worden. Dit vereist natuurlijk een gevoelige detectietechniek om resistentie op te sporen. Aan de hand van een gevoelige detectietechniek kan de diagnose van anthelminthicumresistentie reeds in een vroeg stadium gesteld worden en kan de verspreiding van resistentieallelen in de wormpopulatie tegengehouden of vertraagd worden. In dit artikel worden de beschikbare tests voor de detectie van anthelminthicumresistentie besproken. Er wordt een stand van zaken gegeven van anthelminthicumresistentie bij runderen in België en er worden maatregelen voorgesteld om resistentie te vermijden of te vertragen.

Detection of Theileria annulata in blood samples of native cattle by PCR and smear method in Southeast of Iran.

Theileria annulata, a protozoan parasite of cattle is causes tropical theileriosis. Polymerase chain reaction (PCR) was used to assess the presence and the frequency of T. annulata infection in blood samples obtained from carrier cattle in Kerman, Southeast of Iran. Blood samples were collected in citrate solution from 150 native cattle with mean age of 1year which selected randomly. Primarily, a thin layer smear was prepared from their ear sublime vein blood and was fixed with methanol and stained with Giemsa dye. Blood smears were examined for the presence of parasites, and blood samples were analyzed by PCR. Piroplasmic forms of T. annulata were seen in 16 of 150 (10.66%) by examination the blood smears with light microscope, whereas 68 of 150 (45.33%) cattle were positive by PCR method. All animals that were positive by blood smears were also positive by PCR. Difference between these methods was significant (P<0.05). Our results demonstrate that this PCR assay in diagnosing T. annulata parasites in carrier cattle is more sensitive than method of smear preparation and can be used in epidemiological studies.

Quality of milk of cows in the first lactation vs. presence of anti-Ostertagia antibodies in their milk

Invasions of gastrointestinal nematodes in dairy cows may affect animals productivity. The most frequently detected internal parasite of dairy cattle is Ostertagia ostertagi. The objective of this study was to determine O. ostertagi invasion extensiveness in selected herds of dairy cattle, with special consideration to cows being in the first lactation, and to analyze the milk yield and contents of basic constituents of milk originating from sero-positive cows. Five herds of dairy cattle (403), with different populations of cows, were selected for the study. Invasion extensiveness in particular herds was determined and ranged from 11.9% to 27.27%. Cows being in the first lactation, the udder milk of which was shown to contain anti-O. ostertagi antibodies, were producing on average 470 kg of milk annually less than cows being in the same lactation period. The analysis of results did not confirm the statistical significance of this difference, likewise it did not demonstrate any statistically significant differences in contents of fat, protein and dry matter. Despite a lack of the statistical significance a producer suffers great economic losses. The conducted study proves that the occurrence of O. ostertagi invasion in herds of dairy cattle is a global problem and that it affects cost-effectiveness of milk production.

Molecular characterization of Trypanosoma (Megatrypanum) spp. infecting cattle (Bos taurus), white-tailed deer (Odocoileus virginianus), and elk (Cervus elaphus canadensis) in the United States

In the United States, the generally non-pathogenic trypanosome of cattle is designated Trypanosoma (Megatrypanum) theileri and is distinguished morphologically from Trypanosoma (M.) cervi, a trypanosome originally described in mule deer and elk. Phylogenetic studies of the Megatrypanum trypanosomes using various molecular markers reveal two lineages, designated TthI and TthII, with several genotypes within each. However, to date there is very limited genetic data for T. theileri, and none for the Megatrypanum trypanosomes found in wild ungulates, in the U.S. In this study U.S. isolates from cattle (Bos taurus), white-tailed deer (Odocoileus virginianus) (WTD), and elk (Cervus elaphus canadensis) were compared by ribosomal DNA (rDNA) sequence analysis and their incidence in cattle and WTD in south Texas counties was investigated. Phylogenetic analyses showed clear separation of the bovine and cervine trypanosomes. Both lineages I and II were represented in the U.S. cattle and WTD parasites. Lineage I cattle isolates were of a previously described genotype, whereas WTD and elk isolates were of two new genotypes distinct from the cattle trypanosomes. The cattle isolate of lineage II was of a previously reported genotype and was divergent from the WTD isolate, which was of a new genotype. In La Salle, Starr, Webb, and Zapata counties in south Texas a total of 51.8% of white-tailed deer were positive for trypanosomes by 18S rDNA PCR. Of the cattle screened in Webb County, 35.4% were positive. Drought conditions prevailing in south Texas when the animals were screened suggest the possibility of a vector for Trypanosoma other than the ked (Lipoptena mazamae) and tabanid flies (Tabanus spp. and Haematopota spp.).

Dung beetle (Coleoptera: Scarabaeinae) diversity and seasonality in response to use of macrocyclic lactones at cattle ranches in the mexican neotropics

Abstract Dung beetles provide recognised environmental services in cattle production systems, but can be negatively affected by the pharmaceutical residues found in excreta, particularly macrocyclic lactones (ML). The diversity and seasonal abundance of dung beetle communities were measured using baited pitfall traps and compared at four cattle ranches in Yucatan, Mexico, to assess the possible effects of ML residues. Cattle parasite control was performed at two of these ranches using ML. A total of 93 274 dung beetles from 17 species were collected. The dominant species at all four ranches were Onthophagus landolti and Canthon indigaceus chevrolati. Compared to ranches where ML was not used, total abundance was higher but richness, evenness and diversity were lower at ranches where ML was used. Five other species were identified as potential indicator species for determining whether there was an effect of ML use at the studied ranches. Seasonal patterns differed between beetle communities: those found at non‐ML sites occurred in higher abundances in May and July, while those at ML sites had higher abundances in May and June. This was probably because herds on ML sites were treated with ML to control parasites in early July. The application of ML for controlling cattle parasites was shown to have a negative effect on the diversity and abundance of dung beetles. These results emphasise the need for timing ML use in order to mitigate the adverse impacts on these insects.

Extracts of dedifferentiated cultures of Spilanthes acmella Murr. possess antioxidant and anthelmintic properties and hold promise as an alternative source of herbal medicine

This study reports the antioxidant and anthelmintic activities of Spilanthes cell cultures. Murashige and Skoog medium supplemented with 5.0 μM N6-benzylaminopurine, 1.0 μM 2,4-dichlorophenoxyacetic acid and 1.0 μM α-naphthaleneacetic acid was found to be the best medium to induce dedifferentiation from the leaf cells and for further maintenance of the callus cultures. These cell cultures and in vivo leaves were subjected to solvent extraction by hexane, ethyl acetate, methanol and water, and their extraction yield and total phenolic contents were evaluated. The antioxidant activity of extracts was determined by using 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay. The methanol extracts of in vitro callus and in vivo leaf showed an apparent antioxidant activity and their IC50 values were 1342.9 and 1085.1 μg/ml, respectively. The anthelmintic efficacy of the extracts was also tested using live trematode (fluke) parasites of cattle as the model test material. The aqueous extract of dedifferentiated callus showed a strong anthelmintic activity, which was higher than the activity of the water extract of the field-grown plant. The results of this study verify the potential of Spilanthes as a reservoir of bioactive agents and also substantiate the value of callus cultures as a new source of anthelmintic and antioxidant compounds.

Fatal hepatic tetratrichomoniasis in a juvenile Waldrapp ibis (Geronticus eremita)

Waldrapp ibis (Geronticus eremita) are a critically endangered species, and there are currently more birds in captivity than in the wild. A juvenile, male Waldrapp ibis housed in a mixed-species exhibit was found dead with no premonitory signs. Necropsy revealed extensive necrotizing hepatitis associated with numerous pleomorphic protozoa that were immunohistochemically reactive with antibodies raised against Tritrichomonas foetus, a parasite of cattle. Electron microscopy confirmed the organisms as members of family Trichomonadidae, and sequence analysis of the first ribosomal internal transcribed spacer region (ITS1), 5.8S ribosomal RNA, and ITS2 regions indicated high genetic similarity (96-97%) to members of the Tetratrichomonas gallinarum complex. The animal was born in captivity, and no introductions in this exhibit had occurred since 2009. Other Waldrapp ibis that had contact with the infected male were negative for flagellate infections by fecal examination, thus cross-species transmission is proposed as the source of infection. The host range of the T. gallinarum complex is very large and although the pathogenicity of its members, especially for wild birds, is controversial, these parasites should be considered as a possible cause of acute mortality in Waldrapp ibis. In addition, immunohistochemistry with T. foetus antibodies and molecular diagnostics may be useful tools for preventative veterinary care of endangered bird populations. A greater understanding of the ecology and pathogenesis of this pathogen may also be vital for screening subclinical captive populations and existing wild populations prior to reintroduction efforts.