A study on intestinal helminthes of dogs, foxes and jackals in the western part of Iran

Human infection especially with helminth parasites is an emerging health issue, as the human environment is increasingly shared with infected animals, either pets or wild life. In this survey, the intestinal content of 83 stray dogs, 22 red foxes and 10 golden Jackals collected from the West Azarbaijan, Kordestan and Kermanshah provinces in the west of Iran, were studied for the presence of helminth parasites. The percentage of different species recovered from these animals is listed as follows: From stray dogs: Toxocara canis (6.02%), Toxascaris leonina (32.53%), Ancylostoma caninum (3.61%), Oxynema sp. (1.35%), Rictularia affinis (12.05%), Taenia hydatigena (53.01%), Taenia ovis (7.23%), Taenia multiceps (4.82%), Echinococcus granulosus (13.25%), Dipylidium caninum (38.55%), Mesocestoides lineatus (26.50%) and Macracanthorhynchus hirudinaceus (4.82%). From red foxes: T. canis (4.54%), T. leonina (31.82%), A. caninum (4.54%), Uncinaria stenocephala (13.64%), Oxynema sp. (9.09%), R. affinis (54.54%), Strongyloides sp. (4.54%), Physaloptera sp. (4.54%), T. hydatigena (9.09%), E. granulosus (4.54%), D. caninum (9.09%), M. lineatus (81.82%), Joyeuxiella pasqalei (27.27%), Diplopylidium nolleri (4.54%), M. hirudinaceus (22.72%) and Macracanthorhynchus sp. (9.09%). From golden jackals: T. canis (10%), T. leonina (30%), R. affinis (50%), T. hydatigena (10%), D. caninum (20%), M. lineatus (70%), J. pasqalei (30%.), Alaria canis (10%), M. hirudinaceus (30%) and Macracanthomynchus sp. (10%).

Endohelminth fauna of the marsh frog Rana ridibunda from Lake Hazar, Turkey

In this study, 236 marsh frogs Rana ridibunda collected from Lake Hazar (Elazig, Turkey) at 15 d intervals between March 2001 and February 2002 were examined for endohelminths; of these, 148 (62.71%) frogs were found to be infected with helminths. In total, 9 helminth species (3 trematodes, 5 nematodes and 1 acanthocephalan) were identified. We observed Gorgoderina vitelliloba (prevalence 2.97%) in the urinary bladder, Haematoloechus variegatus (4.66%) and Rhabdias bufonis (8.90%) in the lung, Pleurogenoides medians (1.69%), Oswaldocruzia filiformis (3.81 %) and Acanthocephalus ranae (26.27 %) in the small intestine, Neoxysomatium brevicaudatum (16.95%) and Cosmocercoides sp. (3.39%) in the large intestine, and Eustrongylides excisus (14.41%) in the body cavity and on,the stomach. No helminth was found in the spleen, kidney, gall bladder, liver, heart or muscle. Of the 9 helminth species identified, Acanthocephalus ranae (26.27 %) had the highest prevalence and abundance and Oswaldocruzia filiformis (8.33+/-4.09) had the highest mean intensity.

Helminths in Mesaspis monticola (Squamata: Anguidae) from Costa Rica, with the description of a new species of Entomelas (Nematoda: Rhabdiasidae) and a new species of Skrjabinodon (Nematoda: Pharyngodonidae)

Entomelas duellmani n. sp. (Rhabditida: Rhabdiasidae) from the lungs and Skrjabinodon cortagoensis n. sp. (Oxyurida: Pharyngodonidae) from the intestines of Mesaspis monticola (Sauria: Anguidae) are described and illustrated. E. duellmani is the sixth species assigned to the genus and is the third species described from the Western Hemisphere. It is easily separated from other neotropical species in the genus by pre-equatorial position of its vulva. Skrjabinodon cartagoensis is the 24th species assigned to the genus and differs from other neotropical species in the genus by female tail morphology.

Parasite field study in central Kentucky on thoroughbred foals (born in 2004) treated with pyrantel tartrate daily and other parasiticides periodically

Foals (79), born in 2004 on three thoroughbred horse farms (C, M, and S) in central Kentucky, were fed pyrantel tartrate daily, beginning at about 3 months of age. In addition, other parasiticides [fenbendazole (FBZ), ivermectin (IVM) alone or with praziquantel (PRAZ), oxibendazole (OBZ), pyrantel pamoate (PRT), and moxidectin (MOX)] were given periodically. All treatments were administered by farm personnel. Over a 14-month period, from May 2004 to July 2005, collections (n=989) of feces were made from the foals for determination of presence of internal parasite eggs/oocysts by qualitative and/or quantitative methods. Conclusions on drug activity are based necessarily on considering the combined effect of pyrantel tartrate and the other compounds. For small strongyles, this was related to which specific additional compound was given. Based on the percentage of foals with strongyle-egg-positive feces and/or the level of eggs per gram of feces (EPG) counts for the foals after treatment, drug activity on small strongyles was highest to lowest for MOX, IVM and IVM/PRAZ, FBZ, OBZ, PRT, and FBZ (2x for 5 days). The macrocyclic lactones (MOX and IVM) were highly superior to the other compounds. Some of the strongyle counts were high (over 2,000), especially on one farm (S), during periods when foals received only pyrantel tartrate, but a few days after administration of therapeutic dose rates of the drugs IVM or MOX, they were negative or very low. Ascarid eggs were present in feces of three foals after treatment with a combination of IVM and PRAZ. The qualitative method was more efficient than the quantitative method in detection of ascarid and strongyle eggs in the feces. Prevalence of eggs of ascarids (Parascaris equorum) was low (0, 4, and 31%), of strongyles high (80, 100, and 100%), of Strongyloides westeri very low (only one infected foal), and oocysts of Eimeria leuckarti medium to high (36, 41, and 85%) for the three farms, C, M, and S, respectively. It is uncertain whether the low ascarid prevalence was from activity of pyrantel tartrate and/or the other drugs or to a limited source of infective eggs.

Spatial heterogeneity in parasite infections at different spatial scales in an intertidal bivalve

Spatial heterogeneities in the abundance of free-living organisms as well as in infection levels of their parasites are a common phenomenon, but knowledge on parasitism in invertebrate intermediate hosts in this respect is scarce. We investigated the spatial pattern of four dominant trematode species which utilize a common intertidal bivalve, the cockle Cerastoderma edule, as second intermediate host in their life cycles. Sampling of cockles from the same cohort at 15 sites in the northern Wadden Sea (North Sea) over a distance of 50 km revealed a conspicuous spatial heterogeneity in infection levels in all four species over the total sample as well as among and within sampling sites. Whereas multiple regression analyses indicated the density of first intermediate upstream hosts to be the strongest determinant of infection levels in cockles, the situation within sites was more complex with no single strong predictor variable. However, host size was positively and host density negatively correlated with infection levels and there was an indication of differential susceptibility of cockle hosts. Small-scale differences in physical properties of the habitat in the form of residual water at low tide resulted in increased infection levels of cockles which we experimentally transferred into pools. A complex interplay of these factors may be responsible for within-site heterogeneities. At larger spatial scales, these factors may be overridden by the strong effect of upstream hosts. In contrast to first intermediate trematode hosts, there was no indication for inter-specific interactions. In other terms, the recruitment of trematodes in second intermediate hosts seems to be largely controlled by pre-settlement processes both among and within host populations.

Faecal helminth egg and oocyst counts of a small population of African lions (Panthera leo) in the southwestern Kalahari, Namibia : research communication

An endoparasite survey of a small pride of African lions (Panthera leo) was conducted at Intu Afrika Kalahari Game Reserve, southwestern Namibia, during winter and summer of 2003 and 2004, respectively. Overall, 23 fresh lion scats were collected opportunistically during fieldwork trials. A flotation technique was employed for the diagnosis of parasites. Three nematodes, Ancylostoma braziliense, Gnathostoma spinigerum and Uncinaria stenocephala and two coccidians, Toxoplasma gondii and Isospora felis were recorded. By using the McMaster method for quantification, a maximum number of 14 866 oocysts per gram of faeces was obtained for I. felis during winter 2003. Endoparasite taxa carried by the different individuals in the pride were found to be related to their levels of association. Rates of infection were relatively low as a result of the habitat, semi-captive conditions and earlier sporadic deworming.

Parasite prevalence and richness in sympatric colobines: effects of host density

Factors that influence proximity and the number and duration of contacts among individuals can influence parasite transmission among hosts, and thus parasite prevalence and species richness are expected to increase with increasing host density. To examine this prediction we took advantage of a unique situation. Following the clearing of a forest fragment that supported red colobus (Piliocolobus tephrosceles) and black-and-white colobus (Colobus guereza), the animals moved into a neighboring fragment that we had been monitoring for a number of years and for which we had described the primate parasite community. After the animals immigrated into the fragment, the colobus populations more than doubled and colobus density became almost twice that found in Kibale National Park, Uganda. Despite this increase in host density, the richness of the parasite community did not increase. However, in both colobus species the prevalence of Trichuris sp., the only commonly occurring gastrointestinal parasite, increased. Over the next 5 years the prevalence and intensity of infection of Trichuris sp. in red colobus declined and their population numbers slowly increased. In contrast, the prevalence and intensity of infection of Trichuris sp. increased in black-and-white colobus and remained high following the immigration, and their population size declined. While Trichuris sp. infections are typically asymptomatic, we consider it a possibility that they contributed to the decline of the black-and-white colobus, and that the red colobus may be serving as a reservoir for Trichuris, thereby increasing the infection risk for black-and-white colobus.

A study of helminth parasites in culled cows from Ireland

The objective of this study was to determine the prevalence and intensity of gastrointestinal nematode, lungworm and liver fluke infection in culled cows in Ireland. Abomasa, colorectal contents and livers were collected from 30 to 68 culled beef and dairy cows during autumn 2002 and summer 2003, respectively. Ostertagia ostertagi were found in the abomasa of only three (10%) cows sampled in autumn and in 38 (57%) cows examined in summer. The majority of positive animals had low burdens of O. ostertagi but a few individuals in the group sampled during the summer had a moderate infection (5000-10,000 adult worms). A proportion of the cows in the summer group were also co-infected with small numbers of Trichostrongylus axei. Cooperia oncophora predominated in the recoveries from the larval cultures although O. ostertagi were also recovered. The overall prevalence of Dictyocaulus viviparus was 14%, based on larval identification in faecal samples. Liver fluke, or varying degrees of pathology attributable to Fasciola hepatica, were present in 65% of the livers. The results of this study extend those of previous workers, which were largely limited to dairy cows alone and which focussed on gastrointestinal nematodes and did not include simultaneous infections with lungworm and liver fluke. It was concluded, from the level of polyparasitism evident in this study, that adult cattle should be considered in preventative approaches to bovine helminthosis.

[Gastrointestinal parasites in goat farms from Bergamo province (Lombardy, north Italy)]

A survey on gastrointestinal parasites in goat farms in Bergamo province was carried out from May 2005 to January 2006. Thirty-one dairy goat farms and 836 adult female goats were examined. Faecal sampling was carried out before the antihelminthic treatments, and the sampling times were grouped in three seasonal periods (June-August, September-October and November-March). Faecal exams were carried out by a McMaster method and eggs per gram (EPG) were calculated for each gastrointestinal parasite. Differences in prevalence of Strongylida, Trichuris and Nematodirus were found between farms with goats on pasture and those where animals were permanently housed indoor. Strongyloides spp. showed higher values of prevalence in goats housed indoor. With regard to the sampling seasons, Strongylida eggs were more prevalent in summer while Nematodirus in winter in goats at pasture. Strongyloides occurred more frequently in autumn in stabled goats.

Gastrointestinal parasitic worms in equines in the Paraíba Valley, State of São Paulo, Brazil

Over a period of 12 years, from 1988 to 2000, a total of 20 individual equines (16 horses and 4 mules) were selected at random, from 10 municipalities in the Paraíba Valley, in the State of São Paulo, Brazil, and then subjected to necropsy for collection of gastrointestinal worms. Individual samples of 10% of the intestinal contents were also taken for counting and identifying the species present, and to establish the prevalence of worms in equine species in the Paraíba Valley. In the sample considered, the presence of parasites ranged from 155 to 1249 worms. Tapeworms (Cestoidea) were present in about 85% of the animals studied, and roundworms (Nematoda) in 100% of the individuals. All the tapeworms collected were of one single species, Anoplocephala perfoliata. In the case of the roundworms, the prevalence of individual species was: 100% for Cyathostomineae, 90% for Oxyuris equi, 70% for Strongylus vulgaris, 45% for S. edentatus, 15% for Strongylus equinus, 60% for Triodontophorus sp., 50% for Gyalocephalus capitatus, 15% for Oesophagodontus robustus and Craterostomum acuticaudatum, and 5% each for Parascaris equorum, Probstimayria vivipara, Habronema muscae, and Trichostrongylus axei. No specimens of flukes (Trematoda) were found in any of the animals studied.

[An insight into the epidemiology and economic impact of gastro-intestinal nematodes in small ruminants]

Milk production has been a distinguishing characteristic of sheep breeding since antiquity in the Mediterranean area, including Italy, where prehistoric findings confirm this particular husbandry activity. In Homer's Odyssey, the description of Polifemo's sheep flock organization is remarkably similar to current production systems. The ancient roots of this tradition have grown into an important economic reality, with excellent levels of milk production and apporoximately 65 typical cheeses. It is interesting to note that the Italian word "pecora" (sheep) is believed to have originated from the Latin "pecunia" (money). Although heavy production losses are due to parasitic infections, only 250 papers have been published in the last 50 years in Italy on sheep parasites. Differences in climate, environmental factors and production tecniques may influence infection prevalence, load and pathogenesis. For this reason, prevention must be aimed at the particular epidemiological situation and not simply adapted from current schemes used abroad. The aim of this paper is to illustrate the epidemiology of ovine gastrointestinal nematodes in Italy and to evaluate the economic importance of their control.

Canine intestinal helminths in Finland: Prevalence, risk factors and endoparasite control practices

In this survey, the prevalence of canine gastrointestinal helminths in Finland was investigated by coprological examination (n = 541) and possible risk factors for helminth infections in dogs were analysed. In addition, the dog owners (n = 296) completed a questionnaire about use of anthelmintics, sources of information about parasites and antiparasitic treatments and reasons for choosing the drugs. The prevalence of gastrointestinal helminths was 5.9%. Eggs from four different species were identified in the faecal samples. Toxocara canis eggs were present in 17 dogs (3.1%), Uncinaria stenocephala eggs in 14 dogs (2.6%) and Diphyllobothrium latum eggs in 2 dogs (0.4%). Moreover, one sample contained eggs of Trichuris vulpis (0.2%). Kennel housing and visits abroad were identified as risk factors for T. canis and U. stenocephala infections. Most dogs (86.0%) received anthelmintic treatment at least once a year. Hunting dogs were dewormed least; one-third was treated less than once a year. Approximately, half of the owners occasionally changed the anthelmintic used. The most important trait of the anthelmintic was its broad spectrum, fenbendazole being the most commonly chosen. Veterinarians, dog magazines and dog breeders were the predominant sources of information concerning parasites and deworming strategies.

Immune adaptive response induced by Bicotylophora trachinoti (Monogenea: Diclidophoridae) infestation in pompano Trachinotus marginatus (Perciformes: Carangidae)

Fish have developed protective strategies against monogeneans through immunological responses. In this study, immune adaptive response to parasites was analysed in the pompano Trachinotus marginatus infested by Bicotylophora trachinoti. Hosts were pre-treated with formalin and after 10 days assigned to one of the following experimental treatments: (1) fish infested with remaining eggs of B. trachinoti; (2) fish infested with remaining eggs of B. trachinoti and experimentally re-infested by exposure to T. marginatus heavily infested with B. trachinoti. Samples were collected at 0, 15, and 30 days. Gills were dissected to check the presence of B. trachinoti. Blood was collected for haematological and biochemical assays. Spleen and head-kidney were dissected for phagocytosis assay. The spleen-somatic index was also calculated. Re-infested fish showed a faster and higher parasite infestation than infested ones. The parasite mean abundance at 15 days was 24.86+/-13.32 and 11.67+/-8.57 for re-infested and infested fish, respectively. In both groups, hosts showed an immune adaptive response to parasite infestation that was marked by an increased number of leukocytes. Also, phagocytosis (%) in spleen and head-kidney cells was stimulated after parasite infestation (92.50+/-3.73 and 66.00+/-9.54, respectively), becoming later depressed (77.39+/-6.69 and 53.23+/-9.14, respectively). These results support the hypothesis that monogenean infestation induces a biphasic response of the non-specific defence mechanisms in the pompano T. marginatus. This response is marked by an initial stimulation followed by a later depression of the non-specific defence mechanisms.

[Therapy and anthelmintic resistance]

Treatment against nematode parasites in sheep and goats is reviewed. The main risk factors for parasitic infection in these hosts are briefly outlined. The mechanism of action of the most important chemical groups (imidazothiazoles and pyrimidines, benzimidazoles/ pro-benzimidazoles and macrocyclic lactones) to which the modern anthelmintic drugs belong are illustrated and discussed with particular emphasis on possible selection of anthelmintic resistance. The need for strategic integrated control based also on the epidemiological patterns of parasitism, the composition and the production of the herd (milk, meat, wool) and the potency of the drugs are discussed. The importance of diet and potential alternative control measures (nematophagus fungi and natural compounds such as tannins) are illustrated.

Prevalence of helminth ova in soil samples from public places in Shiraz

To determine the prevalence of helminth eggs in public places and children's playgrounds, 112 soil samples were collected in 26 sites in Shiraz, southern Islamic Republic of Iran, during September 2002-September 2003. Toxocara cati ova were found in 7 (6.3%) samples, 2 had Ascaris lumbricoides ova, 3 had larvae morphologically similar to Strongyloides stercoralis. Coccidia oocysts were also observed in 4 samples. No contamination was observed during the dry season.

Survey of helminths in adult sheep in Heilongjiang Province, People's Republic of China

The prevalence of helminths in adult sheep was investigated in Heilongjiang Province, People's Republic of China between January 1999 and September 2003. A total of 326 adult sheep representing local breeds (Xingjiang Fine Wool Sheep, Dongbei Fine Wool Sheep) as well as introduced breeds (Merino and Charollais) from representative geographical locations in Heilongjiang Province were slaughtered and examined for the presence of helminths. The worms were examined, counted and identified to species according to existing keys and descriptions. A total of 26 helminth species were found representing 2 phyla, 3 classes, 13 families and 20 genera. All sheep were infected by more than one helminth species. Oesophagostomum columbianum, Haemonchus contortus and Trichostrongylus colubriformis were the most common nematode species, and Paramphistomum cervi, Orientobilharzia turkestanica and Fasciola hepatica were the most common trematode species, whereas the infection of adult sheep with cestodes was uncommon. The results of the present investigation provide relevant "base-line" data for Heilongjiang Province, China, for assessing the effectiveness of future control strategies against helminth infections in sheep.

Effect of age, sex and season on the prevalence and intensity of helminth infections in domestic pigeons (Columba livia) from Bursa Province, Turkey

The one-year study reported in this paper was carried out from April 2002 to March 2003 in domestic pigeons (Columba livia) of Bursa Province (Turkey) to determine the occurrence of helminth species and to evaluate the effect of host age, sex and season on their prevalence and intensity. A total of 100 (31 young and 69 adult) domestic pigeons were necropsied and examined. The results of necropsies revealed that 74 pigeons harboured helminth infections. Three helminth species were identified: Baruscapillaria obsignata (63%), Ascaridia columbae (42%) and Raillietina echinobothrida (1%). There were no significant differences in the prevalence of B. obsignata and A. columbae by host age and sex. Significantly the highest prevalence rate of A. columbae was observed in the autumn months, but there was no significant difference in the seasonal prevalence of B. obsignata. The mean intensity of B. obsignata and A. columbae was higher in adults than in young pigeons but it did not differ significantly between the two sexes. The highest mean intensity rate of B. obsignata was observed in the autumn, while there was no significant difference for A. columbae with regard to season. From the data obtained in this study it can be concluded that in regions with similar climatic conditions as those in the present study area, pigeon breeders should be cautioned especially of B. obsignata and A. columbae infections of adult pigeons in the autumn months.

HELMINTHS OF SYMPATRIC STRIPED, HOG-NOSED, AND SPOTTED SKUNKS IN WEST-CENTRAL TEXAS

Twenty-eight hog-nosed skunks (Conepatus leuconotus), 23 striped skunks (Mephitis mephitis), and nine spotted skunks (Spilogale gracilis) from an area of sympatry in west-central Texas were examined for helminth parasites. Shared helminth species among all three host species were one nematode (Physaloptera maxillaris), two acanthocephalans (Pachysentis canicola, Macracanthorhynchus ingens), and one cestode (Mathevotaenia mephitis). Two nematodes (Gongylonema sp. and Filaria taxidaea) occurred in both the striped and hog-nosed skunks. One nematode (Filaroides milksi) and one acanthocephalan (Oncicola canis) were collected only from C. leuconotus. The most common helminth infections for striped and hog-nosed skunks were P. maxillaris and P. canicola. Helminth species richness was highest in hog-nosed skunks, but striped skunks had the highest prevalences and intensities of all the common helminth species. The helminth fauna of spotted skunks was markedly depauperate in terms of species richness and helminth abundance compared to the other two host species. Differences in helminth communities across these three sympatric skunks may be related to differences in their relative abundance, behavior, food habits, and geographic range.

Variation in infection parameters among populations within parasite species: Intrinsic properties versus local factors

Within any parasite species, variation among populations in standard infection parameters (prevalence, intensity and abundance) is an accepted fact. The proportion of hosts infected and the mean number of parasites per host are not fixed values across the entire geographic range of any parasite species. The question is whether this inter-population variation occurs within a narrow, species-specific range and is thus driven mainly by the biological features of the parasite, or whether it is substantial and unpredictable, leaving population parameters at the mercy of local conditions. Here, the repeatability of estimates of prevalence, intensity and abundance of infection was assessed across populations of the same parasite species, for 77 metazoan parasite species of Canadian freshwater fishes. Overall, parameter values from different populations of the same parasite species were more similar to each other and more different from those of other species, than expected by chance alone. Much of the variation in parameter values in the dataset was associated with differences between parasite species, rather than with differences among populations within species. This was particularly true for intensity and abundance of infection; in contrast, prevalence values, while somewhat repeatable among populations of the same species, still showed considerable variation. Among the higher taxa investigated (monogeneans, trematodes, cestodes, nematodes, acanthocephalans, copepods), there was no evidence that species of one taxon display intrinsically greater variation in population parameters than species of other taxa. Overall, the results suggest that intensity and abundance of infection are real species characters, though somewhat variable. This conclusion supports the view that the biological features of parasite species can potentially override local environmental conditions in driving parasite population dynamics.

[The helminth and coccidial fauna of pheasants (Phasianus colchicus) in view of the specific environmental conditions in pheasantries and in the wild]

Between October 1999 and January 2000 all together 151 male pheasants were examined for endoparasites. 33 one-year-old birds came from two pheasantries, the remaining 118 birds, aged between one and five years, were wildlife animals. The infestation extensy of all pheasants with endoparasites were 96.7%. A mostly low infestation with coccidia of the three species Eimeria (E.) phasiani, E. duodenalis and E. tetartooimia were detected in 41% of all birds. E. tetartooimia was found in Germany for the first time. In 67.5% of the pheasants the five different species of capillaria (Capillaria (C.) annulata, C. bursata, C. contorta, C. perforans, C. phasianina) and in 84.1% the nematode Heterakis gallinarum were present. Pheasants in the capture group showed higher infestation intensy and extensy. In 51.5% of the pheasants of the capture group Syngamus trachea was present. In one pheasant an acanthocephalus (Plagiorhynchus cylindraceus) was detected for the first time in Germany and in two pheasants a trematode of the genus Echinostoma was present.

Occurrence of hydatidosis in slaughter buffaloes (Bos bubalis) and helminths in stray dogs in Kathmandu Valley, Nepal

The study aimed at identifying the occurrence of hydatidosis in slaughter buffaloes and helminth eggs, particularly Taenia spp. eggs in stray dogs' fecal samples in Kathmandu Valley, Nepal. The study period was from November, 2004 to April, 2005. A total of 500 buffalo carcasses in a slaughterhouse, at the riversides and individual butchers'sites were examined for the presence of hydatid cysts. The cyst fluid was collected and microscopically examined to determine if it was fertile or not. Of the 500 carcasses examined, 10.6% had hydatid cysts. Specifically, the slaughterhouse carcasses had a 6.7% occurrence of hydatid cysts, whereas those examined at riversides and individual butcher places had 10.0% and 12.7%, respectively. Distributions of the hydatid cysts by specific organs showed single occurrence of 6.4% in lungs, 2.4% in livers and 1.8% in both, livers and lungs. In a total of 53 infected buffaloes, 58.5% were fertile and 41.5% sterile cysts. Overall, 366 faecal samples from stray dogs were collected around buffaloes slaughtering areas (slaughterhouse and individual butcher places), riversides, garbage sites and temple sites. These samples were examined by formalin-ether concentration technique to investigate the presence of different helminth eggs. The total prevalence of Taenia, hookworms, Trichuris/Capillaria,Toxocara, Spirometra and Physaloptera eggs were 12.8%, 18.3%, 19.1%, 12.8%, 1.4% and 1.9%, respectively.

Prevalence and significance of gastrointestinal helminths and protozoa in South American Camelids in Switzerland

A cross sectional study was conducted to determine the prevalence and significance of endoparasitic infections in South American Camelids (SAC) in Switzerland. Qualitative and quantitative coproscopic examinations were performed in 38 farms during the grazing period. Management practices with possible interference with parasitic infections were analyzed. On the farm level prevalences of endoparasitic infections were: trichostrongyles 87%; Trichuris sp. 74%; Capillaria sp. 68%; Nematodirus battus 63%; Nematodirus sp. 53%; Dicrocoelium dendriticum 34%; Moniezia sp. 8%; Fasciola hepatica 5%; protostrongylids 5%; Eimeria macusaniensis 68%. The level of helminth egg excretion was generally low. The highest values were recorded for trichostrongyles with an average of all investigated farms of 53 eggs per gram of faeces. The mean trichostrongyle egg output was approximately three-fold in SAC on farms that also kept sheep and/or goats, although this difference was not significant (P = 0.11). Clinical trichostrongylidosis was not reported from any of the farms. The low infection level with gastrointestinal nematodes is attributed to the defaecation behaviour of the SAC depositing their faeces focally on small spots on pasture. As a consequence, pasture infectivity is largely restricted to the area adjacent to the dung piles. Dicrocoeliosis is regarded as the most relevant parasitic infection of llamas and alpacas in Switzerland causing severe clinical symptoms and death in untreated animals. Sixteen per cent of the owners regularily treated their herds against dicrocoeliosis using praziquantel at a dose of 50 mg/kg body weight orally.

Studies on the interaction between Salmonella enterica ser. Typhimurium and intestinal helminths in pigs

Concomitant infections with helminths and bacteria may affect the course and the resulting disease outcome of the individual infections. Salmonella, Oesophagostomum, Trichuris and Ascaris coexist naturally in pig herds in Denmark, and possible interactions were studied. Pigs in one experiment were trickle infected with low or moderate dose levels of Oesophagostomum spp. and challenge infected with S. Typhimurium. In another experiment, pigs were inoculated with S. Typhimurium followed by a challenge exposure to either Oesophagostomum, Trichuris or Ascaris. Enhancement of the Salmonella infection was not demonstrated in either experiment. The helminth effect on the pigs was modest and may explain the lack of influence on the Salmonella infection. A previous experiment with a larger Oesophagostomum infection level resulted in enhancement of the S. Typhimurium infection. A dose dependency of the interaction is therefore suggested. However, the relatively high worm burdens in the present study suggest that infection with these common pig helminths does generally not influence the course of concurrent S. Typhimurium infections under natural conditions.

INFLUENCE OF HOST AGE AND SEX ON THE HELMINTH FAUNA OF THE YELLOW-LEGGED GULL (LARUS MICHAHELLIS) IN GALICIA (NORTHWESTERN SPAIN)

We studied the influence of host age and sex on the helminth fauna of 324 Larus michahellis captured in different locations in the region of Galicia (northwestern Spain). Gulls were grouped into prefledglings, first-year immature birds, second- and third-year immature birds, and adults. Second-year, third-year, and adult birds were grouped by sex. Thirty-six helminth species were recorded. Total species richness and mean infracommunity species richness were both significantly lower for pre-fledglings than for the other age groups. Prevalence increased significantly with age for Brachylecithum microtesticulatum, probably reflecting changing feeding habits. Likewise, 8 species (Cardiocephaloides longicollis, Microphallus similis, Maritrema gratiosum, Gynaecotyla longiintestinata, Brachylecithum microtesticulatum, Himasthla elongata, Parorchis acanthus, and Renicola sp.) were absent or had very low prevalence in prefledglings. At least 5 of these 8 species are transmitted to gulls through ingestion of molluscs or crustaceans, which suggests that these types of prey are seldom fed to prefledglings. In Gymnophallus deliciosus, G. longiintestinata, and Cosmocephalus obvelatus, mean intensity, and in the latter case prevalence, declined with age, suggesting that protective immunity against these species increase with age. Only G. deliciosus, Microphallus similis, and G. longiintestinata presented significant differences between the sexes.

GEOGRAPHIC ANALYSIS OF HOST USE, DEVELOPMENT, AND HABITAT USE OF AN ACANTHOCEPHALAN SPECIES, LEPTORHYNCHOIDES THECATUS

Leptorhynchoides thecatus (Linton, 1891), an acanthocephalan parasite of freshwater fishes, varies in host use, development, and habitat use throughout North America. Spatial structure of these characteristics was examined from data extracted from the literature. Geographic patterns were inferred from point comparisons using correllograms and then tested with Moran's I statistic for global and local significance, and visually from regional means within major river drainages. Species of Micropterus Lacepède, 1802 (black basses) were common hosts in most regions, except the Lower Mississippi and South Atlantic regions where species of Lepomis Rafinesque, 1819 (sunfishes) were common hosts. Development, described as the proportions of adults relative to cystacanths (extraintestinal juveniles), decreased with latitude. Habitat use of L. thecatus showed marked geographic patterns. Leptorhynchoides thecatus occurred in the intestine of sunfishes in the South Atlantic and Lower Mississippi regions, in the ceca in fish of all species included in the study in the Missouri and Texas-Gulf regions, and both in ceca and intestines in fish of all species in northern regions. Leptorhynchoides thecatus showed geographic patterning within the variable traits across the range of the species. These patterns may be the result of ecological factors or of genetic differences that might indicate L. thecatus comprises multiple cryptic species.