Tick infestations on livestock in the yemen arab republic and their potential as vectors of livestock diseases

A survey of ticks on cattle, camels, sheep, goats and donkeys in four different geographical locations of the Yemen Arab Republic (YAR) was carried out to provide more information on the possible risk of tick-borne diseases to imported exotic cattle included in the YAR's plans for livestock development. The most abundant ticks were Hyalomma spp. particularly on camels. Ticks found on cattle included Hyalomma spp., Amblyomma variegatum, Boophilus annulatus and Rhipicephalus spp. In general with the exception of camels tick burdens on all species of domestic livestock were very low. Two hundred and ninety eight serum samples from miscellaneous adult cattle throughout the country were negative to a test for Anaplasma marginale antibodies. It is speculated that tick burdens in the YAR are too low for significant disease transmission and the implications of the findings are discussed.     

The epidemiology of nematode and fluke infections in cattle in the Red River Delta in Vietnam

Over a period of 13 months, faecal samples were collected monthly from approximately 45 cattle over 3 months of age. Additionally, 74 calves of 1-2 months were sampled to determine the presence of Toxocara vitulorum eggs. Individual egg counts and infective strongyle larvae from pooled faecal samples were examined. Post-mortem worm counts were carried out on six groups of tracer calves (n=12) that had been kept for 4 weeks on pasture in and around the village studied. The following helminths were identified: T. vitulorum, Cooperia punctata, C. pectinata, C. oncophora, Oesophagostomum radiatum, Trichostrongylus axei, T. colubriformis, Haemonchus spp., Fasciola spp. and Paramphistomum spp. In 8% of the samples collected from young calves, individual egg counts for T. vitulorum were found indicative for pathogenic worm burdens. Strongyle egg counts and worm counts indicated that transmission is low without a distinct seasonality. In animals of 3-9 months old, a strongyle egg count peak can be demonstrated which at a higher age steadily and significantly decreased. In faecal cultures Cooperia spp. were most prominent in all age groups throughout the year with the exception of the period September-November when Haemonchus spp. and Oesophagostomum spp. were most prevalent. Fasciola spp. eggs were found in 22% of the collected faecal samples and the egg counts were low indicating that the intensity of Fasciola spp. infection is mild. Based on the present data, regular anthelmintic treatments seem not to be justified, except for a single treatment at the age of 2 weeks against toxocariosis.     

Efficacy of a topical formulation of ivermectin against naturally acquired gastro-intestinal nematodes in weaner cattle

The efficacy of a topical formulation of ivermectin against naturally acquired gastro-intestinal nematodes in weaner cattle was evaluated. At slaughter, 14-15 days after treatment, burdens of Ostertagia spp, Trichostrongylus axei and Oesophagostomum radiatum were significantly lower in the treated calves than in the untreated controls (p<0.01). Efficacies (based on geometric mean worm burdens of treated and control groups) were 99.6%, 95.1% and 100% respectively. The sizes of the Cooperia spp and Trichuris ovis burdens in the treated group did not differ significantly at the 5% level of confidence from those in the control group.     

Parasites of domestic and wild animals in South Africa. VI. Helminths in calves on irrigated pastures on the transvaal highveld

Sets of tracer calves, which were exposed for 2 months on irrigated pasture and then slaughtered, provided evidence of the extent of seasonal helminth infestation. Haemonchus spp. were the most abundant nematodes, the largest numbers of which were generally recovered from May--August. Marked inhibition of development in the 4th larval stage was noted from May--November. Trichostrongylus spp. were recovered in modest numbers with the highest burdens generally present in May, June and October. In the first year of the survey Cooperia spp. were recovered in small numbers, but in the second year burdens increased from February--June.     

The helminths of ranch calves in the North-eastern Mountain Grassland of South Africa

The cumulative total helminth parasite burdens of ranch calves during their first seven months of life on the North-eastern Mountain Grassland of South Africa were determined during two consecutive years. Trichostrongylus axei was the most abundant nematode parasite followed by Cooperia spp. and Ostertagia ostertagi. Haemonchus spp. occurred in relatively low numbers and its development was significantly inhibited. The total helminth parasite burdens of the calves ranged from 681 to 7,269 with a mean of 4,405.     

Dynamics of Ostertagia spp. and Cooperia oncophora in field-grazed cattle from weaning to 2 years old in New Zealand, with particular reference to arrested development

Gastrointestinal nematode parasite burdens were monitored in a herd of field-grazed cattle from weaning to 2 years old to allow observations to be made on the dynamics of burdens of arrested Ostertagia spp. and Cooperia oncophora. Arrested Ostertagia spp. accumulated in the herd over their first autumn and winter to reach a peak in late winter/spring (August-October). From October until late January they declined at a rate comparable to that at which they had accumulated. Numbers continued to decline at a slower rate until the following autumn (May) when they began to increase again. Observations on the decline of worm burdens in a group of animals which had been moved from pasture to worm-free conditions in October indicated that intake of infective larvae over late spring/summer contributed little to the number of arrested Ostertagia spp. in the herd. No clinical Type II ostertagiosis was observed in the field-grazed animals over the time of decline of the arrested worm burden, nor was there an increase in the number of adult Ostertagia spp. present. However, two of the animals removed from pasture to worm-free conditions developed Type II ostertagiosis approximately a month after the move. Worm burdens of successive groups of "tracers" grazed with the herd every 2 months indicated that there was a small seasonal increase in the propensity of Ostertagia spp. for arrested development. However, estimated accumulation rates of arrested larvae calculated from tracer worm burdens, suggest that this seasonal increase in propensity was not adequate in itself to account for the accumulation rate observed in "resident" animals of the herd. No comparable accumulation of arrested C. oncophora took place in resident animals over the first autumn and winter of the trial despite the fact that tracer worm burdens over this period indicated a marked seasonal increase in the propensity for arrested development by this species.     

Studies on the parasites of zebras. III Nematodes of the mountain zebra from the farm "Kelpie" and the Namib-Naukluft Park, South West Africa/Namibia

Twelve mountain zebra which were culled at monthly intervals on the farm " Kelpie " in South West Africa/Namibia were examined for helminths. The zebras varied in age from 2-15 years, the middle group of which, aged 4-7 years, had the highest worm burdens. Fourteen species of nematodes belonging to the families Atractidae , Strongylidae , Oxyuridae , Setariidae and Spiruridae were recovered. The highest worm burdens were those of Crossocephalus sp. with 692-61 066 680 and Probstmayria vivipara with 1 257 810-42 004 300. The predominance of the atractids is discussed. The nematodes consistently present were: Cylicodontophorus n. sp. (44-2 107), Triodontophorus spp. (2-934), Cylindropharynx spp. (20-2 332), Crossocephalus sp. and P. vivipara. Two new species, Cylicostephanus longiconus and Cylicodontophorus n. sp., were reported. An additional 3 mountain zebra, culled in the Namib - Naukluft Park, were also examined for helminths. Of 3 zebras ranging in age from 2-7 years, the 2 older animals had the highest helminth burden. Ten species of the nematodes belonging to the same families mentioned above were recovered. The only Spiruridae present were 3 Habronema majus in 1 zebra. The highest worm burdens were those of Crossocephalus sp. with 64 052-883 070 and P. vivipara with 50 720-220 200. The nematodes consistently present were the same as those in the " Kelpie " zebra. In addition, a 2nd, new species of Cylicodontophorus was reported.     

The natural regulation of Trichostrongylus spp. populations in young grazing sheep

The dynamics of Trichostrongylus axei and intestinal Trichostrongylus spp. were studied in grazing lambs over a 2-year period. Monthly comparisons were made between worm counts of experimental lambs continuously exposed to infection from 3 to 7 months of age, and tracer lambs which were allowed to graze on the experimental plots for successive 4-week periods.It was found that irrespective of the level of larval intake, experimental lambs were unable to regulate their worm burdens until at least 5 months of age. When larval intake was high, resistance to establishment of larvae apparently occurred at approximately 6 months of age followed by rejection and resistance to reinfection. In conditions of low larval intake, worms accumulated with no apparent control operating in lambs up to 7 months of age.These results suggest that a rapid turnover of worm populations does not occur in Trichostrongylus spp., and that in young lambs, worms accumulate until sufficient exposure to infection stimulates resistance to larval establishment and ultimately rejection of adults.     

The use of herbal preparations for tick control in western Ethiopia

Information on the traditional tick control methods used in Keffa, Illubabor and Wellega Provinces in western Ethiopia was obtained from 86 veterinary clinics and 865 peasant farmers through a questionnaire survey. Latexes of Euphorbia obovalifolia and Ficus brachypoda, juice of crushed leaves of Phytolaca dodecandra and Vernonia amygdalina, fruit juice of Solanum incanum, crushed seeds of Lepidium sativum mixed with fresh cattle faeces, juice of crushed leaves and bark of Calpurnea aurea and commercially available spice of Capsicum spp. mixed with butter, were used by peasant farmers to control ticks. Preliminary in vitro efficacy tests of these plant preparations were performed on engorged female Boophilus decoloratus. Preparations of Capsicum spp., E. obovalifolia, S. incanum and F. brachypoda were found to have 30-100% killing effects. Subsequently, in vivo treatment trials of these preparations were conducted using indigenous Bos indicus cattle naturally infested with ticks. Results indicate that treatments at the rate of once per day for 5 consecutive days with the latexes of E. obovalifolia and F. brachypoda can reduce tick burdens by up to 70% on cattle.     

Results of parasitological examinations of faecal samples from horses, ruminants, pigs, dogs, cats, hedgehogs and rabbits between 1998 and 2002

The results of coproscopical examinations in horses, ruminants, pigs, dogs, cats, hedgehogs and rabbits between 1998 and 2002 are presented. In 4399 samples from horses 37.4% stages of strongylids, 1.4% anoplocephalids, 1.3% Strongyloides westeri, 0.9% Parascaris equorum, 0.04% Oxyuris equi, 0.04% Eimeria sp. and 0.04% Fasciola hepatica were found. In 998 samples of cattle 22.1% stages of strongylids, 11.2% of Eimeria spp., 3.5% of cryptosporidium, 2.9% of Moniezia spp., 1.3% of Trichuris spp., 0.7% of Dictyocaulus sp., 0.6% of Fasciola hepatica, 0.6% of Strongyloides sp., 0.5% of Nematodirus spp. and 0.4% of Capillaria sp. could be detected. In 524 samples of sheep 60.7% eggs of strongylids, 43.1% oozysts of Eimeria spp., 11.1% stages of Nematodirus spp., 9.5% of Moniezia spp., 7.8% of Trichuris spp., 6.7% of Strongyloides sp., 1.7% of Fasciola hepatica, 1% of Capillaria spp., 0.4% of protostrongylidae, 0.2% of Skrjabinema sp. and 0.2% of Dictyocaulus sp. were found. 33.9% of the 118 samples of goats that were examined were positive for oocysts of Eimeria spp., 30.5% for eggs of strongylids, 6.8% for Nematodirus spp., 4.2% for Trichuris spp., 3.4% for Moniezia spp., 0.8 for protostrongylids and 0.8% for Strongyloides sp. 5.7% of 1427 samples of pigs contained stages of strongylids, 1.5% of Ascaris suum, 0.4% of Isospora, 0.3% of Eimeria spp., 0.3% of Trichuris sp., 0.1% of Giardia sp., 0.1% of cryptosproidium as well as 0.1% of metastrongylids. In 1281 of the samples of dogs 2.3% Giardia sp., 2.3% Isospora sp., 2.2% Toxocara canis, 1.4% ancylostomids, 0.8% taeniids, 0.6% larvae of Crenosoma sp., 0.2% Capillaria sp, 0.2% Trichuris vulpis and 0.2% Hammondia-like oocysts were found. In 441 samples of cats 10.7% stages of Isospora sp., 3.9% eggs of Toxocara cati, 1.6% of ancylostomids, 1.4% of taeniids, 1.1% of Giardia sp., 0.7% of Toxoplasma-like oocysts, 0.7% of Aelurostrongylus abstrusus, 0.5% of Toxascaris leonina and 0.2% of Capillaria spp. were found. Furthermore 0.2% of the samples contained proglottids of Mesocestoides and 0.2% stages of Dipylidium sp. Eggs of Capillaria sp. were found in 33% of the 106 samples of hedgehogs, larvae of Crenosoma striatum in 27.4%, oocysts of Isospora sp. in 5.7% of the cases. In 232 samples of rabbits 56.9% oocysts of Eimeria sp., 4.8% stages of Passalurus ambiguus, 1.3% of strongylids, 0.9% of Strongyloides sp., 0.4% of trematodes were found.     

郑州地区冷季型草坪草根腐病病原鉴定

通过对郑州地区冷季型草坪草根腐病病原物分离鉴定发现,主要病原物有镰刀菌(Fusarium spp.)、链格孢菌(Alternaria spp.)、丝核菌(Rhizoctonia spp.)、德氏霉菌(Drechslera spp.)、弯孢菌(Curvularia spp.)和腐霉菌(Pythium spp.)6大类。其中,茄腐镰刀菌(Fusarium solani)和立枯丝核菌(Rhizoctonia solani)(AG-4)的分离频率最高,致病力比较强,为优势病原。     

SEASONAL CHANGES IN THE STRUCTURE OF NEMATODE POPULATIONS OF CATTLE IN NEW SOUTH WALES IN RELATION TO INHIBITED LARVAL DEVELOPMENT

Pasture plots in 3 climatic regions were contaminated with worm eggs of Ostertagia ostertagi, Trichostrongylus axel, Haemonchus spp and Cooperia spp in the autumn, winter and spring. Successive pairs of parasite-free calves were grazed on the plots for 7 to 10 days at 4-week intervals and then killed for worm counts 14 days after their removal from pasture.
On the Northern Tablelands of New South Wales, irrespective of the season of pasture contamination, the degree of inhibition of O. ostertagi was low in winter and highest in spring. T. axei showed similar trends while Cooperia spp showed negligible inhibition.
On the North Coast of New South Wales, inhibited larvae accounted for a very small proportion of the O. ostertagi burdens, while in comparison T. axei showed a much greater degree of inhibition. Larval inhibition of Haemonchus spp occurred in autumn and early winter after which it did not occur. There was negligible inhibition in Cooperia spp.
On the Central Coast of New South Wales, there was little inhibition of O. ostertagi and none in T. axel . For Haemonchus spp, inhibited larvae were found mainly in autumn and winter. The numbers of inhibited Cooperia larvae were also highest in autumn and winter and were associated with large worm burdens.
The marked difference between the tablelands and coastal regions in the seasonal trends of inhibition of O. ostertagi was considered to be due to a difference in strains between the geographical regions. The possible effect of climatic factors on the inhibition-proneness of infective larvae on pasture is discussed for Ostertagia and other nematodes. The roles of host resistance and density-dependence are also discussed.     

A survey of intestinal parasites in dogs from Saskatoon, Saskatchewan

Fresh fecal samples from 124 apparently healthy dogs and 333 random source canine fecal samples from dog walking areas were analyzed by centrifuged flotation in Sheather's solution to determine the prevalence of gastrointestinal parasites in dogs from Saskatoon, Saskatchewan. Fecal flotation was positive in 4.4% of samples. Roundworm species were found in 1.5% of samples, hookworm species were found in 0.4% of samples, whipworm species were found in 0.7%, Strongyloides spp. were found in 0.6%, Giardia spp., Cystoisospora spp., and Alaria spp. were found in 0.4% of samples.     

Fecal shedding and antimicrobial susceptibility of selected bacterial pathogens and a survey of intestinal parasites in free-living waterfowl

Free-living waterfowl residing in metropolitan parks in central Ohio were surveyed for the fecal shedding and antimicrobial susceptibility patterns of Campylobacter jejuni, Escherichia coli, Salmonella spp., and Pasteurella multocida. In addition, a survey for intestinal parasites was also conducted in these same waterfowl to determine parasite burdens in free-living waterfowl. Prevalences of 67%, 50%, and 0.2% of E. coli, C. jejuni, and Salmonella spp., respectively, were observed for all waterfowl species. Pasteurella multocida was not isolated from the sampled population. Salmonella java was isolated from one mallard duck. Statistically, there was a significantly higher E. coli isolation rate for mallard ducks than for Canada geese, but no difference was observed for C. jejuni isolation rates between waterfowl species. Antimicrobial susceptibility testing was conducted via the disk diffusion method and multidrug resistance was exhibited for penicillin G, lincomycin, vancomycin, erythromycin, and bacitracin. In addition, the prevalence of endoparasites in these sampled waterfowl ranged from 5% to 66%. Protozoan oocysts were most prevalent followed by nematode ova. No trematode or cestode ovum was recovered from this sampled population.     

Helminth parasites of beef cattle in the East Kimberley and Victoria River Districts of Northern Australia

An investigation into the helminth species present in cattle in the East Kimberley and Victoria River Districts of Northern Australia was conducted over a 2-year period based on bi-monthly total and differential worm counts in weaner cattle as well as on a post mortem survey of adult cattle sent for slaughter. The most important species found in young cattle were Haemonchus placei and Cooperia spp. Only small numbers of Bunostomum phlebotomum, Nematodirus spathiger, Oesophagostomum radiatum and Moniezia benedini were present. Calicophoron calicophorum and nodules of Onchocerca spp. and Oe. radiatum were recorded in adult cattle. Seasonal fluctuations in helminth parasite burdens are discussed in relation to temperature and rainfall and the results are interpreted in relation to the effects of helminthosis on present and future beef production in this area.     

Helminthiases in newly established large-capacity breeding stations for cattle]

Invasions of gastrointestinal nematodes proved to be the most frequent helminthiases in new-established large-capacity herds of cattle according to the results of parasitary examinations of cattle in one locality in the Tachov district. The nematodes, especially Oesophagostomum spp., Haemonchus contortus, Cooperia spp., Trichostrongylus spp., occurred in animals of all age categories. The Ostertagia spp., Chabertia ovina, Nematodirus spp., Bunostomum phlebotomum and Trishuris spp. participated in the invasions to a smaller extent. The first eggs can already be found in three months old calves. Strongyloidosis can be diagnosed in the first month of age in calves [5%], the incidence rate increasing up to the age of five months, then it begins to decrease. Taenasis was found out in six months old calves [4.4% and11.6%]. Reclamations of pastures reduced the incidence of fasciolosis to the minimum rate; its invasions were heavy before establishing the large-capacity herds of cattle. Dictyocaulosis was not found in the large-capacity herds of cattle at all, due to the same reasons. Not only were nematode eggs proved, but also larvae to develop to the stages capable of invasion [Chabertia ovina, Haemonchus contortus, Oesophagostomum spp., Strongyloides papillosus] in dry excrements on railings of pens, on slatted floors and walls of the calf-sheds that were investigated.     

Dynamics of pasture contamination by gastrointestinal nematodes of cattle under extensive management systems: proposal for strategic control.

An epidemiological study of gastrointestinal nematode parasitism in beef cattle in mountainous areas of Spain was performed. The dynamics of contamination with gastrointestinal nematode larvae of Pyrenean pastures was studied over four years at five areas at different altitudes (900 m to 2100 m), grazed by animals according to traditional systems of beef cattle in mountainous areas. Grass samples were taken every two weeks and larval differentiation was performed. Worm egg counts of grazing animals were assessed in cows, heifers and calves. A consistent seasonal pattern of infective larvae on pasture through the study was observed. In hay meadows, located below 1000 m, infective larvae were found from the end of October until June of the following year. At higher altitudes (1200-2100 m), a bimodal pattern of pasture larvae contamination was observed with increases in late spring (March-June) and in late autumn (September-November). Ostertagia spp., Cooperia spp., Trichostrongylus spp., Oesophagostomum spp., and Nematodirus spp. were found, with Ostertagia spp. being the most frequently found, followed by Cooperia spp. The highest increase of larval contamination in autumn coincided with the grazing of animals in hay meadows. This elevated autumn larval population had a very important epidemiological role because these larvae remained as overwintered larvae until the following grazing season, starting the cycle of contamination of the animals.     

Evidence‐based considerations for control of Parascaris spp. infections in horses

Parascaris spp. infection is virtually ubiquitous in young foals and worm burdens can achieve high numbers. The most important disease manifestation is impaction of the small intestine, which occurs in a small proportion of infected foals but is associated with a guarded prognosis for survival. Control of Parascaris spp. is complicated by emerging resistance to currently available anthelmintic drug classes. Resistance to macrocyclic lactones has been reported worldwide and a few studies have also documented signs of resistance to pyrantel salts and benzimidazoles. Foals generally develop immunity to Parascaris spp. parasites around age 6 months, but a proportion of weanlings and yearlings can harbour smaller burdens at age 8–10 months. Older horses have occasionally been reported with substantial ascarid burdens as well. Qualitative detection of ascarid eggs has good diagnostic value whereas an actual egg count does not correlate well with the size of the worm burden. A recent investigation documented the applicability of a transabdominal ultrasound technique for semiquantitatively monitoring ascarid burdens in foals. Control of ascarids is complicated by the limited drug classes available for treating this parasite, and by the fact that foals are often concurrently infected with strongyles. In many cases, none of the 3 available anthelmintic classes are simultaneously effective against both parasite groups, so close monitoring is required to select the most appropriate anthelmintic in each case.     

Parasitic health of olive baboons in Bwindi Impenetrable National Park, Uganda

This study examined the endoparasite load of a group of olive baboons (Papio cynocephalus anubis) that share their habitat with a population of mountain gorillas (Gorilla gorilla berengei) in Bwindi Impenetrable National Park, Uganda. During a 2-week period in June 2002, shared habitat was substantiated by noting the ranging patterns of both species and recording observations and trail remains with a global positioning system (GPS). Parasite load was determined by collecting fecal samples preserved in 10% formalin and analyzed by sedimentation techniques and immunofluorescent antibodies (IFA). Bwindi baboons were infected with Cryptosporidium, Giardia, Eimeria, Ascaris spp., Strongyloides spp., Trichuris spp., Hymenolepis spp., and Ternidens diminuta. Of these, the Bwindi mountain gorillas had previously been found to carry Cryptosporidium, Giardia, Strongyloides spp., and Trichuris spp., but not Eimeria, Ascaris, Hymenolepis, or T. diminuta. This study is the first to record Giardia in olive baboons and demonstrates that at least three parasite species in Bwindi baboons have yet to be found in Bwindi gorillas. Early monitoring is essential to the health and well being of both of these sympatric primate species, especially as they continue to interact more often and over a larger area.     

Safety and efficacy against fourth-stage gastrointestinal nematode larvae, of monepantel in 6-week old lambs

A controlled, blinded study was undertaken in 6-week old, pre-weaned lambs to demonstrate the safety and efficacy against fourth-stage gastrointestinal nematode larvae, of monepantel administered per os at 2.5mg/kg body weight. Worm burdens of 10 monepantel-treated lambs were compared to those from 10 untreated control lambs. Geometric mean derived efficacies of 100, 100, 96.4 and 99.9% were demonstrated against Haemonchus contortus, Teladorsagia spp., Cooperia curticei and Trichostrongylus colubriformis, respectively. These results, considered in the light of an earlier series of studies demonstrating the efficacy of monepantel in older animals, and an absence of any adverse events, provides strong support for the use of monepantel as a safe and effective anthelmintic in lambs from six weeks of age.