Macroparasites in cetaceans stranded on the northwestern Spanish Atlantic coast

An extensive parasitological survey was carried out during autopsy of 80 cetaceans representing 8 species within 4 families (Delphinus delphis, Stenella coeruleoalba, Tursiops truncatus, Grampus griseus, Globicephala melas, Kogia breviceps, Phocoena phocoena and Megaptera novaeangliae) collected on the northwestern Spanish Atlantic coast from February 1991 to October 1996. Two species of tetraphyllidean cestodes (Phyllobothrium delphini and Monorygma grimaldii), 2 ascaridoid nematodes (Anisakis simplex and A. physeteris), a single spirurid nematode (Crassicauda magna), 4 rhabditidiform nematodes (Halocercus delphini, H. invaginatus, Halocercus spp. and Stenurus globicephalae), a single polymorphynae acanthocephalan (Bolbosoma sp.), and 2 amphipods (Isocyamus delphini and Cyamus boopis) were found. This paper presents 6 new geographic records of macroparasites from cetaceans in temperate Atlanto-Iberian waters. A total of 11 component parasite species were found, mainly parasitizing the blubber, mesentery and stomach of cetaceans. Cetaceans harboured a suite of 4 generalist and 8 specialist species.

Comparative performance of species richness estimation methods

In most real-world contexts the sampling effort needed to attain an accurate estimate of total species richness is excessive. Therefore, methods to estimate total species richness from incomplete collections need to be developed and tested. Using real and computer-simulated parasite data sets, the performances of 9 species richness estimation methods were compared. For all data sets, each estimation method was used to calculate the projected species richness at increasing levels of sampling effort. The performance of each method was evaluated by calculating the bias and precision of its estimates against the known total species richness. Performance was evaluated with increasing sampling effort and across different model communities. For the real data sets, the Chao2 and first-order jackknife estimators performed best. For the simulated data sets, the first-order jackknife estimator performed best at low sampling effort but, with increasing sampling effort, the bootstrap estimator outperformed all other estimators. Estimator performance increased with increasing species richness, aggregation level of individuals among samples and overall population size. Overall, the Chao2 and the first-order jackknife estimation methods performed best and should be used to control for the confounding effects of sampling effort in studies of parasite species richness. Potential uses of and practical problems with species richness estimation methods are discussed.

Northern bobwhites as disease indicators for the endangered Attwater's prairie chicken

Because of limited access to the endangered Attwater's prairie chicken (Tympanuchus cupido attwateri), we used a related species, the northern bobwhite (Colinus virginianus), as a surrogate for disease evaluation. Free-living northern bobwhites (n = 62) on the Attwater Prairie Chicken National Wildlife Refuge (near Eagle Lake, Texas, USA) were examined during spring and fall 1993 for helminthic endoparasites and specific antibodies against the infectious agents responsible for nine infectious diseases. Trichostrongylus cramae, Raillietina sp., and Strongyloides avium were collected from 97, 44, and 32% of northern bobwhites examined, respectively. Dispharynx nasuta and Syngamus trachea also were found. No gross lesions due to parasites were observed. Specific antibody to Pasteurella multocida was found in 3 of 53 plasma samples. It is possible that potentially pathogenic species such as P. multocida, T. cramae, and D. nasuta could threaten sympatric Attwater's prairie chickens.

Latitudinal differences in species and community richness and in community structure of metazoan endo- and ectoparasites of marine teleost fish

Relative species diversity of gastrointestinal helminths of 55 teleost fish species did not differ significantly at different latitudes, whereas relative species diversity of metazoan ectoparasites on the heads and gills of 108 teleost fish species showed a significant increase with decreasing latitude and from deep to surface waters. Abundance of endoparasites also was the same at all latitudes, whereas abundance of ectoparasites increased with decreasing latitude and from deep to shallow waters. A comparative analysis using phylogenetically independent contrasts supported these conclusions. Possible reasons for the differences between endo- and ectoparasites are discussed. A detailed analysis of the community structure of gastrointestinal helminths of five Antarctic and three tropical teleosts and of metazoan ectoparasites on the heads and gills of five Antarctic and seven tropical fish species showed the following: abundance and prevalence of infection of endoparasites are similar in Antarctic and tropical fish, but are much greater for tropical than for Antarctic ectoparasites. Relative species diversity of endoparasites is similar for Antarctic and tropical endoparasites, but much greater for tropical than Antarctic ectoparasites. In both Antarctic and tropical fish, different fish of the same species may have different dominant species of endo- and ectoparasites, although there is a greater range of dominant species of tropical ectoparasites, a consequence of the greater species pool available. The most dominant parasite (irrespective of species) represented 80-99% of all endoparasites of Antarctic, and about 50-80% of all endoparasites of tropical fish. The most dominant parasites (irrespective of species) represented about 90-100% of all ectoparasites of Antarctic, and about 20-70% of all ectoparasites of tropical fish, the difference a consequence of the greater species pool of tropical ectoparasites available. The data suggest that both endo- and ectoparasites live in assemblages not structured by interspecific competition.

Gastrointestinal helminth parasites in stray cats from the mid-Ebro Valley, Spain

Gastrointestinal helminths were collected from 58 necropsied stray cats (Felis catus) in the mid-Ebro Valley, North-East Spain, from December 1989 to March 1992. The prevalence was 89.7%, with those of individual parasites being Toxocara cati 55.2%C, Ancylostoma tubaeforme 29.3% Joyeuxiella pasqualei 55.2%, Diplopylidium acanthotetra 20.7%, Dipylidium caninum 20.7%, Mesocestoides spp. 13.8%, Taenia taeniformis 8.6% and Diplopylidium nölleri 8.6%. In relation to sex, the differences were not significant. However, the season of the year significantly affected the prevalence of A. tubaeforme and D. acanthotetra.

The contributions of host age and size to the aggregated distribution of parasites in yellow perch, Perca flavescens, from Garner Lake, Alberta, Canada

The independent effects of host age and size on parasite abundance are examined in yellow perch from Garner Lake in east-central Alberta. Older, larger perch tend to have more species of parasites combined with larger parasite infrapopulations. Sexual size dimorphism in perch generates 2 different size classes within each age class >2+ yr, thus allowing the opportunity to separate the effects of age and size on the recruitment of parasites by perch. The abundances of Diplostomum adamsi and Bothriocephalus sp. both increase with host age, whereas the increased abundances of Crepidostomum isostomum and Raphidascaris acus in larger fish are, in part, suggestive of size-specific feeding behaviors of the host. A combination of parasites with size- and age-dependent infrapopulations results in a size-dependent increase in infracommunity size. A comparison of variance-to-mean ratios within age classes to overall variance-to-mean ratios shows that the effects of host age and size on parasite recruitment do contribute to parasite aggregation.

Helminth parasites of conventionally maintained laboratory mice--II. Inbred strains with an adaptation of the anal swab technique

Worm burdens recovered from inbred mice strains, namely C57Bl/6, C57Bl/10, CBA, BALB/c, DBA/2 and C3H/He, conventionally maintained in two institutional animal houses in the State of Rio de Janeiro, RJ, Brazil, were analyzed and compared, regarding their prevalences and mean intensities. Three parasite species were observed: the nematodes Aspiculuris tetraptera, Syphacia obvelata and the cestode Vampirolepis nana. A modification of the anal swab technique is also proposed for the first time as an auxiliary tool for the detection of oxyurid eggs in mice.

Origin of an insular population of the wood mouse based on parasitological evidence

Parasitological data were used to test the hypothesis that the wood mouse (Apodemus sylvaticus) population of Fair Isle, Shetland, originated from the British Isles rather than Scandinavia, as is usually argued. This study was based on the assumption that the mice were likely to share most of their parasite fauna with conspecifics from their ancestral home. The ecto- and endo-parasites of wood mice on Fair Isle between 18 June to 10 July 1987 and 17 to 26 August 1991 were identified and compared with those reported from conspecifics in the two putative source areas. All eight species of metazoan parasites that infected A. sylvaticus on Fair Isle were common to mice of the British Isles, whereas just one parasite on Fair Isle, a mite, had been recorded from Scandinavia. This lends support to the hypothesis that the mice originated from Britain rather than Scandinavia.

Serologic and parasitologic survey of the endangered Attwater's prairie chicken

Because conservation biologists have postulated that infectious diseases may have potentiated the endangerment of the Attwater's prairie chicken (Tympanuchus cupido attwateri), free-living prairie chickens were surveyed from all remaining populations for helminthic endoparasites and antibody against the etiological agents of nine infectious diseases. Samples from 4 of 27 adult males were positive for anti-Pasteurella multocida antibody. All other serologic tests were negative (n = 19). We identified Dispharynx nasuta, a parasite previously associated with disease in other grouse from North America, in one of three adult Attwater's prairie chickens examined. Evidence of Trichostrongylus cramae was found for eight of nine suitable samples, which represents the first report of this parasite in prairie grouse. The mean intensity of T. cramae in Attwater's prairie chicken was 1,019.3 (Range = 3-1,906; n = 3). Further work is needed to determine whether P. multocida, T. cramae, or D. nasuta are detrimental to Attwater's prairie chicken populations. If so, conservation biologists could reduce the prevalence and incidence of these parasites and potentially gain more time to address the habitat conditions thought to be the ultimate cause of population declines.

Helminth surveillance as a prerequisite for anthelmintic treatment in intensive sow herds

Helminth prevalences in pigs in intensive production systems are often very low due to housing and management factors, and the present study was carried out to examine whether routine anthelmintic treatment in such herds can be replaced by coprological surveillance of the helminth status combined with anthelmintic treatment when necessary. After an initial examination, 25 out of 28 large herds of Danish sows (> or = 50 sows, production of fatteners) were found to have such light helminth infections that routine deworming could be replaced experimentally by coprological examination every 6 months of 10 weaners (10-12 weeks old), 10 fatteners (5-6 months old), 10 dry sows and 10 lactating sows. This coprological surveillance continued in 21 herds of the selected 25 herds for a 3-year period, while it was stopped immediately in one herd due to increasing Ascaris suum prevalences, and ceased after one year in three herds due to other reasons. A. suum was found in all but one of the 25 herds. The most heavily infected age group was the sows, in which the A. suum prevalence was consistently low in approximately half of the herds, while it increased slowly or rapidly in the other half. When this happened, treatment of the breeding stock was recommended which resulted in low prevalences for varying periods of time. Few farmers neglected the recommendations for some time or for all 3 years, which resulted in consistently high prevalences in the sows (e.g. 40-60%). The fatteners were in general more lightly infected with A. suum than the sows, and in approximately 3/4 of the herds the prevalence remained at a low level, while it fluctuated in the remaining herds. No weaners were ever found to excrete eggs, most likely due to unfavourable conditions for egg development in the farrowing pens. Throughout the study Oesophagostomum sp. eggs were found sporadically in the sows of two herds, and in a third herd, Oesophagostomum sp. was introduced after 2 years, probably due to close contact with a neighbour herd. Oesophagostomum sp. was not found in the remaining herds. Eggs of Trichuris sp. were found sporadically. In conclusion, it is recommended that veterinarian advisers evaluate the production systems before suggesting an anthelmintic routine. If helminth infections may be controlled by intensive management and housing alone, coprological surveillance combined with anthelmintic treatment when necessary may replace routine use of anthelmintics. If the surveillance reveals that the infection levels continue to be low unnecessary medication is avoided, and if the infection levels increase, the coprological data obtained can be used to optimize the anthelmintic strategy.

Parasites of South African wildlife. XV. Helminths of scrub hares, Lepus saxatilis in the Kruger National Park

A total of 145 scrub hares from three localities in the Kruger National Park were examined for helminths: 124 at Skukuza, 15 at Shingwedzi, and three each at Pretoriuskop and Pafuri. Trichostrongylus deflexus was the most prevalent and most abundant nematode, and was collected from hares from all four localities. Trichostrongylus falculatus was present in three localities. Trichostrongylus thomasi and Dermatoxys vlakhaasi occurred only at Skukuza in 50 and 23%, respectively, of the hares examined. The cestode Mosgovoyia pectinata and the nematode genus Impalaia were each recovered from three localities and Cooperia hungi from two. There was no apparent seasonal pattern of abundance of the worms, and the intensities of infection of male and female hares were similar. With the exception of D. vlakhaasi, all the helminths recovered in this study represent new records for scrub hares in South Africa.

A survey to identify the important macroparasites of rock partridge (Alectoris graeca saxatilis) in Trentino, Italy

A preliminary survey of the intestinal helminth community of rock partridge (Alectoris graeca saxatilis) was undertaken in the Italian province of Trentino where the host population exhibits cyclic fluctuations in abundance. Six helminth species were recorded from 38 rock partridge intestines collected during the hunting season between October and November 1994. Nematoda were the most prevalent (53%) with lower prevalence of Trematoda (11%) and Cestoda (8%). Ascaridia compar (Schrank, 1790) and Heterakis tenuicauda Linstow, 1883, were identified as the component species (each with prevalence > 10%) in the helminth intestinal community of rock partridge in Trentino. Both of these species exhibit an aggregated distribution.

Endoparasites of plethodontid salamanders from Paradise Brook, New Hampshire

Totals of 52 dusky salamanders Desmognathus fuscus, 51 two-lined salamanders Eurycea bislineata, 54 red-backed salamanders Plethodon cinereus, and 3 spring salamanders Gyrinophilus porphyriticus (Plethodontidae) collected in June and August 1995 from Paradise Brook, a tributary to Hubbard Brook, New Hampshire, were examined for parasites. Parasites found were Brachycoelium storeriae, Brachycoelium sp., Bothriocephalus rarus, Falcaustra sp., Omeia sp., Batracholandros magnavulvaris, and Cepedietta michiganensis. Eighty-six percent of the red-backed salamanders, a terrestrial species, harbored 1 or more parasites. Among the aquatic and semiaquatic species, 27% of the dusky and 45% of the two-lined salamanders were infected with 1 or more parasites.

Helminth and arthropod parasites of sandy fox, Vulpes ruppeli (Fissipedea; Carnivora) from Sohag, with redescription of Platynosomum fastosum (Digenea: Dicrocoeliidae)

Forty-seven Vulpes ruppeli from two rural areas neighbouring the poultry farms in Sohag, Egypt were examined for helminth and arthropod parasites. A total of ten species of helminths (4 trematodes, 3 cestodes and 3 nematodes) and six species of arthropod ectoparasites (one louse, 3 fleas and one tick) were found. Redescription of the trematode parasite, Platynosomun fastosum Kossack 1910, which was recovered for the first time in Sohag, was the most important point. Data were discussed.

Impact of abomasal nematodes on roe deer and chamois body condition in an alpine environment

Abomasal helminths were examined from 101 roe deer and 43 chamois, shot or found-dead, in the period July-November 1993-95, in the Parco Naturale Paneveggio Pale di San Martino (Italian Eastern Alps). Twelve helminth species were observed in both roe deer and chamois. For both host species, discriminant analysis, using the abundance of each parasite species in the hosts, failed to distinguish between subjects from each of the three study years. For 44 roe deer and 27 chamois data on body weight, body length, foot length, withers height, thoracic circumference and kidney fat index were also available. Principal Component Analysis was performed on the biometrical data in order to group related variables into a few compound variables. In both host species it was possible to identify two principal components, with an explained variance > 80%: the first component, led by body length, was an expression of skeletal development and the second, led by kidney fat index, of nutritional status. Parasite abundance and richness appeared to be negatively correlated with the scores of both skeletal and nutritional Components in the two host species, although only the correlation between parasite abundance and the scores of the nutritional component in roe deer was statistically significant (Spearman r = -0.411; p < 0.05). These results support the susceptibility of roe deer to abomasal helminths, which could be important considering the spatial and nutritional interspecific competition between domestic and wild ruminants often recorded in alpine environments.

Control by management

It is currently possible to reduce significantly the number of anthelmintic treatments required by grazing ruminants by employing some relatively simple management procedures, enlightened by knowledge of the epidemiology of the parasites in the climatic region and production system in question. Some examples of these procedures, such as the Michel dose and move system for nematode control in cattle, strategic treatments at times of low larval availability for sheep and alternate grazing of sheep and cattle will be considered. While such procedures can have a major impact on frequency of anthelmintic treatment, they rarely have a commensurate effect on reducing selection for anthelmintic-resistant worms. Only in control systems that avoid the use of anthelmintics altogether is there any certainty of avoiding selection for resistance. The nearest approaches to this ideal goal are some alternate grazing schemes and rotational grazing systems currently being tested in tropical environments. Even if these anthelmintic-free production systems are successful, the worms are still being selected for attributes that may ultimately render these control procedures ineffective. Examples of this are the propensity for alternate grazing systems to select for reduced host specificity, or increased numbers of parasite species able to infect both host species. Similarly, rotational grazing systems could be subverted by selection for enhanced larval survival or faster development from egg to infective larva. Nevertheless, it is hoped that selection for such fundamental changes as those presumably required to affect survival, development or host specificity will be slower than selection for anthelmintic resistance.

Occurrence of cystacanths of Polyacanthorhynchus kenyensis larvae (Acanthocephala) in four teleostean fishes from a tropical lake, Lake Naivasha, Kenya

From January 1992 to December 1993, a total of 2158 fish, namely Oreochromis leucostictus (Trewavas, 1983), Micropterus salmoides (Lacépède, 1802), Tilapia zillii (Gervais, 1848) and Barbus amphigrama (Boulenger, 1902) were sampled from thirteen stations on Lake Naivasha, Kenya, using a fleet of gill nets and examined for helminth parasites. The prevalence of infection due to cystacanths of an acanthocephalan, Polyacanthorhynchus kenyensis Schmidt et Canaris, 1967 among parasitized O. leucostictus ranged from 30.4 to 86.9%; among T. zillii from 4.1 to 77.7%; in M. salmoides from 20 to 50%; and in B. amphigrama from 5.8 to 100%. In 735 hosts belonging to the above four species, a total of 4198 immature specimens of P. kenyensis were recovered. All cystacanths were found in extraintestinal sites, either free within the fish body cavity or encysted within the host visceral organs. There was no significant variation in the prevalence of the parasite within months (P > 0.001). Host sex ratio was significant (P < 0.001) in favour of male T. zillii, and also highly significant (P < 0.001) in favour of male O. leucostictus. Moreover, in this fish, prevalence of infection was observed to increase with the increase in the size of the fish. Among infected M. salmoides, there was no significant departure from a 1:1 sex ratio.

A comparative analysis of parasite species richness of Iberian rodents

Data on parasites of rodents, collected over an 18-year period on the Iberian peninsula, were used to find the determinants of parasite species richness. A total of 77 species of helminth parasites (nematodes, cestodes and digeneans) was identified among 16 species of rodents. Parasites were classified into groups according to their specificity towards their host and their life-cycle. A working phylogeny of the rodents was proposed on the basis of molecular and paleontological data and for each host the following parameters were recorded: sample size, weight, geographical range, longevity, and life-style. Two comparative methods were used, the independent comparisons method of Pagel (1992) and the distance matrix method of Legendre, Lapointe & Casgrain (1995). The second method has the advantage of measuring the relative contribution of phylogeny. Both methods gave similar results. Overall parasite species richness correlated only with host sample size. Host body size does not correlate with any subset of parasite species richness. However, host phylogeny is a good predicator of specific parasites and the species richness of digeneans correlates with host geographical range. A phylogenetic reconstruction of host relations was performed using the parasites belonging to subgroups in which richness is correlated with host phylogeny. These parasite species were treated as Dollo characters, i.e. we made the assumption that the loss of a parasite species is irreversible. The consensus tree obtained reflects the major phylogenetic divisions of the host group. Finally, this study illustrates the relative importance of processes acting at different temporal and spatial scales (evolutionary time and actual geographical range of hosts) in determining the structure of helminth parasite fauna.

A survey on resistance to anthelmintics in sheep stud farms of southern Brazil

A survey to investigate the status of anthelmintic resistance in 29 sheep studs in southern Brazil was conducted from March 1992 to December 1993. Compounds from three drug families (macrocyclic lactone, levamisole and benzimidazole) were evaluated concurrently on 22 of the 29 studs. On seven of these properties, resistance to all three families was declared or suspected; at 15 of the 22 studs, ivermectin was the only compound found to be effective in reducing faecal egg counts. Resistance to levamisole was detected on 22 of the 23 studs where it was evaluated and was suspected in the remaining one. The position of benzimidazoles was similar, resistance being declared or suspected on all 28 studs where they were tested. Results of larval cultures indicated that Trichostrongylus, Ostertagia and Haemonchus were the most prevalent nematode genera in the survey, with Trichostrongylus and Haemonchus being the genera associated with anthelmintic resistance.

A multidisciplinary approach using several biomarkers, including a parasite, as indicators of pollution: a case history from a paper mill in Newfoundland

Several biomarkers are currently used to determine chronic exposure of fish to environmental contaminants. In studies to assess the effects of pulp mill effluent on winter flounder (Pleuronectes americanus), body and hepatosomatic indices (HSIs), histopathology, levels of hepatic detoxifying enzymes, mixed function oxygenases (MFO), muscle acetylcholinesterase (Ache) and selected parasite abundance were compared in samples taken near a paper mill (sulphite-bleaching) and a number of reference sites. Our studies revealed a number of significant (P < 0.05) differences between samples taken near the paper mill and reference sites. Flounder captured at two locations near the mill were greater in length and weight, had elevated HSIs and more lesions in the liver and spleen while an acanthocephalan, Echinorhynchus gadi, located in the digestive tract, was lower than at more distant sites. Activity of MFO and Ache were similar at most sites and might be a reflection of the fish's foraging behaviour and consequently intermingling of populations from different locations during summer. These results support the view that several biomarkers should be utilised when assessing the health of fish living in habitats degraded by pollutants.

Biodiversity of parasites in freshwater environment in relation to pollution

During 1994, 129 specimens of chub (Leuciscus cephalus L.) from two localities, polluted--Bolelouc, 80th river kilometer, near the city of Olomouc, and unpolluted--Brodské, 225th river kilometer, near the Lanzhot on the Morava river, were examined for metazoan parasites. Altogether 38 metazoan parasite species including helminths, leeches and glochidia belonging to 14 genera were found, 34 in the case of unpolluted locality (Brodské) and 28 in the polluted one (Bolelouc). In both localities, 24 parasite species (Dactylogyrus folkmanovae, D. naviculoides, D. prostae, D. vistulae, D. vranoviensis, Gyrodactylus carassii, G. gasterostei, G. gracilihamatus, G. scardiniensis, G. vimbi, Gyrodactylus sp., Paradiplozoon ergensi, P. homoion, P. megan, Paradiplozoon sp., Caryophyllaeus brachycollis, Diplostomum spathaceum--larval stage, Philometra abdominalis, Acanthocephalus anguillae, Pomphorhynchus laevis and Glochidium sp.) were found, 10 (D. crucifer, D. nanoides, G. hemibarbi, G. lamberti, G. leucisci, G. lomi, P. rutili, C. fennica, A. imitans, S. bramae) were identified solely in the unpolluted locality Brodské and 4 (D. fallax, G. laevis, P. ovata, G. kearni) parasite species were found only in the polluted locality Bolelouc. Differences in parasite species richness, the level of dominance, the structure of core and in satellite species were observed. Current methods of statistical evaluation were used.

Helminthosis in local and cross-bred pigs in the Morogoro region of Tanzania

We investigated the prevalence, burden and types of gastro-intestinal helminths in 424 local and cross-bred pigs kept under different management systems in two climatic zones in the Morogoro region of Tanzania. Coprological examination revealed that 53% of the pigs excreted helminth eggs in their faeces. The median eggs per gram of faeces (EPG) was 500 (range 100-22,000). Local breeds in the Mgeta location with tropical highland climate showed significantly higher prevalence (P < 0.001) and median EPG values (P < 0.001) than the cross-bred animals in the semi-arid area. There was no significant difference in the prevalence (P = 0.90) of helminth infection and egg outputs (P = 0.78) in cross-bred pigs raised under the small-scale and semi-intensive management systems in the semi-arid zone. Piglets showed significantly lower prevalence of helminthosis (P < 0.001) than the weaners, growers and adults in both local and cross-bred animals. Median EPGs of growers and adult animals were significantly higher than those of piglets and weaners (P = 0.006). The prevalences of various helminth species were Oesophagostomum sp. (40%), Ascaris suum (12%), Strongyloides ransomi (9%) and Trichuris suis (5%).

[Endoparasitic fauna and incidence of species in yearling and adult horses in Upper Bavarian breeding farms with regular anthelmintic prophylaxis lasting for many years]

In this epidemiological study 127 horses from five breeding farms in Upper Bavaria were included. The horses were coproscopically examined in intervals of four weeks over a 16-month period. Since 1992 in all farms regular prophylactic treatments with anthelmintics have been carried out. In 127 horses at least five species were established, such as Parascaris equorum, Anoplocephala perfoliata, Gasterophilus intestinalis and small strongyles, whose third stage larvae were characterized by eight or twelve intestinal cells. Infections with small strongyles occurred most frequently, followed by G. intestinalis, A. perfoliata and P. equorum. Seven horses excreted eggs of P. equorum, three yearlings, and a two, four, five and seven year old animal, each. 113 of the 127 examined horses showed infections with strongyles, hence, almost all animals of the farms I-V. The evaluation of horses with strongyle infections as regards to the frequency of the coproscopically established eggs revealed a high incidence independent of age. The maximal epg-values showed no obvious age-dependent differences varying between < or = 67 and 3733. The horses excreted strongyle eggs with epg-values of > or = 333 predominantly during the summer. With an epg-value of > or = 333, independently of age the 23 horses treated with Ivomec-P as well as 20 of the 24 horses given Banminth remained coproscopically negative three to four weeks after treatment. The animals treated with Rintal or Panacur continued to excrete strongyle eggs three to four weeks following the anthelmintic application. The use of anthelmintics in horses with epg-values < 333 revealed analogous results. Infections with A. perfoliata were established in all farms, altogether in 32 horses independently of the age of the animals. Eggs of G. intestinalis have been observed only in two farms, but almost in all horses there.

Helminths of wintering geese in Texas

Ten Canada geese (Branta canadensis), 24 snow geese (Chen caerulescens) and 22 white-fronted geese (Anser albifrons) from coastal Texas (USA) were examined for helminths. Three cestode, seven nematode, and three trematode species were collected. Gizzard nematodes (Amidostomum anseris, A. spatulatum and Epomidiostomum crami) infected 53 of 54 birds. Gross lesions were not attributed to helminth infections and the host population does not appear to be impaired by them.

Helminths and arthropods of black and white rhinoceroses in southern Africa

Helminths and arthropods were collected and quantified from two black rhinoceroses (Diceros bicornis bicornis) and one white rhinoceros (Ceratotherium simum), and ticks from an additional four black and two white rhinoceroses in southern Africa. The helminths of a black rhinoceros from the Republic of South Africa and one from Namibia were quantitatively measured and recorded for each compartment of the alimentary tract. Probstmayria vivipara was the most abundant parasite in each animal. A recently described nematode, Diceronema versterae, was found in the stomach of one animal. Draschia megastoma was present in the descending colon of the same animal, but it was twice the size of similar specimens reported from equids and the typical granulomatous lesions caused by this nematode in horses were not observed. New records of other helminths from rhinoceroses include Parabronema roundi, Kiluluma sp., Kiluluma goodeyi, Kiluluma magna, Khalilia rhinocerotis, Oxyuris karamoja and Anoplocephala gigantea. The stomach bot, Gyrostigma pavesii, was collected from one black and one white rhinoceros. Ticks collected from the black rhinoceroses were Amblyomma hebraeum, Dermacentor rhinocerinus, Rhipicephalus maculatus, Rhipicephalus muehlensi and Haemaphysalis silacea. The two white rhinoceroses were infected with A. hebraeum, D. rhinocerinus, Hyalomma truncatum, Rhipicephalus simus, Rhipicephalus appendiculatus and Rhipicephalus zambeziensis.