[Trematodes of birds (Aves) from the Middle Volga region. 1. Orders Brachylaimidae, Cyclocoelida, Echinostomatida, Notocotylida, and Opisthorchiida]

The data on trematodes of the orders Brachylaimidae, Cyclocoelida, Echinostomatida, Notocotylida, and Opisthorchiida from the Middle Volga region are given. Records of different authors are supplemented with the results of our own research. Reliable records are confirmed for 61 trematode species. The following characteristics for each parasite species are given: the systematic position, the host spectrum, locality, collecting sites, biology, degree of host specificity, and the geographical range. Morphological descriptions and original figures of 3 trematodes species are given.

Dynamics of infestation of tracers lambs by gastrointestinal helminths under a traditional management system in the North of Tunisia

The authors present a survey of gastrointestinal helminths of sheep on permanent pastures in the extreme north region of Tunisia (Mediterranean climate). Dynamic infestation of animals has been monitored by using batches of three tracer lambs introduced each two months during 2004 and 2005. These lambs were kept in the pens of veterinary school of Sidi Thabet (Tunisia) during three months and then necropsied. Faecal and blood samples were took from tracer lambs each two months during the whole period, and from animal flock only during 2004. The main helminth genera encountered were Trichostrongylus spp., Teladorsagia spp., Strongyloides papillosus and Anoplocephalidea; occasionaly were found Nematodirus, Oesophagostomum, Chabertia, Cooperia, Trichuris and Paramphistomum. The egg count of the ewes and lambs in the flock showed two peaks. For both ewes and lambs there is a gradual increase from January with a peak in May-June. This first peak is considered to be due to acquisition of infective larvae during the rainy and cold season, as evident from the worm burdens of tracer lambs. The second peak was exclusively observed in ewes during late autumn-early winter (November-December); it has two origins: infestation by third larvae stage and the periparturient rise. The worm burdens of tracer lambs showed that there was a gradual accumulation of nematodes from September-October, reaching a peak in March-April; a very low or naught infection is reported during the dry period (July-August). Infection by Anoplocephalidea was higher during the dry season. This study is primordial for a comprehensive control programme implementation against gastrointestinal helminths.

[Monitoring of the helminth of insectivorous mammals of meliorative canal banks in Belorussian Polesie]

The helminth fauna of insectivorous mammals inhabiting meliorative canal banks has been examined in western part of Belorussian Polesie during 2005-2010. 33 species of helminthes were found in 4 species of small mammals, and total infection was 94.2%. The results of monitoring were compared with the observations carried out in the same territory in 1996-1999. Common shrew was found to be the dominant species among insectivorous mammals. The helminth complex in the insectivorous mammals inhabiting meliorativ canal banks is formed mainly from the helminths of this host species.

Manipulating small ruminant parasite epidemiology through the combination of nutritional strategies

It is increasingly being recognized that non-chemical parasite control strategies may need to be combined to control more effectively gastrointestinal parasitism, result in resilient production systems and reduce reliance on anthelmintics. Here, we consider if and how metabolizable protein (MP) supplementation and anti-parasitic plant secondary metabolites (PSM) may modulate parasite epidemiology through intervention in pasture contamination, development of infection on pasture and larval challenge as target processes. We then propose that combining two or more non-chemical parasite control strategies may have additive effects on host resistance, especially if the individual strategies target different drivers of parasite epidemiology, different processes in the parasite life cycle or different phases of acquired immunity to parasites. This epidemiological framework is used to review recent findings on combining maternal MP supplementation and grazing the PSM-rich bioactive forage chicory as an example of combining nutritional treatments to manipulate parasite epidemiology in a temperate production system. In the absence of available data for combined nutritional strategies in tropical production systems, we make predictions on the consequences of combining such strategies in these systems. We conclude that currently published studies on combining nutritional strategies under temperate conditions show potential to improve additively host resilience and reduce reliance on anthelmintics; however, effects on epidemiology have to date not shown the additive results hypothesized. The framework developed may assist further in evaluating combined (nutritional) strategies to manipulate parasite epidemiology.

Host social rank and parasites: plains zebra (Equus quagga) and intestinal helminths in Uganda

The main aim of this study was to evaluate the relationship between the social hierarchy of plain zebra, Equus quagga, and the level of parasitism. For the study 141 fecal samples from the same number of animals were collected within the two major populations of E. quagga of Uganda (Lake Mburo Conservation Area and Kidepo Valley National Park). Quantitative (eggs per gram of feces) and qualitative parasite assessment were performed with standard methods. The relationship between parasite burden and individual host features was analyzed using Generalized Linear Models. Strongyles, cestodes, Strongyloides sp. and oxiurids where present in the examined samples. Social rank and age class significantly affect all parasites' abundance with dominant individuals being less parasitized than subordinate individuals, regardless of the parasite groups excluding oxiurids. Sex could not been shown to be related with any of the found parasites. Age was positively related with strongyles and oxiurids abundance and negatively related with cestodes and Strongyloides sp. The main result of the present study was the evidence that social status influences parasite level with dominant zebras shedding less parasite eggs than subordinate ones. Social rank appears, therefore, as an important factor giving rise to parasite aggregation in plain zebras.

Helminth communities from two urban rat populations in Kuala Lumpur, Malaysia

BACKGROUND

The prevalence of parasitic infections among commensal animals such as black and brown rats in many tropical countries is high and in comparison with studies on rodents in temperate climates, little is known about the community structure of their parasites. Rodent borne parasites pose threats to human health since people living in close proximity to rodent populations can be exposed to infection.

METHODS

The helminth community structures of two urban rat populations in Kuala Lumpur, Malaysia were investigated. The rats were from two contrasting sites in the city caught over a period of 21 months in 2000-2002.

RESULTS

Eleven species of helminth parasites comprising seven nematodes (Heterakis spumosum, Mastophorus muris, Nippostrongylus brasiliensis, Syphacia muris, Pterygodermatites tani/whartoni, Gongylonema neoplasticum, Angiostrongylus malaysiensis), three cestodes (Hymenolepis (Rodentolepis) nana, H. diminuta and Taenia taeniaeformis) and one acanthocephalan (Moniliformis moniliformis) were recovered from 346 Rattus rattus and 104 R. norvegicus from two urban sites, Bangsar and Chow Kit, during 2000-2002. Rattus rattus harboured over 60% of all helminths compared with R. norvegicus, although both host species played a dominant role in the different sites with, for example R. norvegicus at Bangsar and R. rattus at Chow Kit accounting for most of the nematodes. Overall 80% of rats carried at least one species of helminth, with the highest prevalences being shown by H. diminuta (35%), H. spumosum (29.8%) and H. nana (28.4%). Nevertheless, there were marked differences in prevalence rates between sites and hosts. The influence of extrinsic (year, season and site) and intrinsic (species, sex and age) factors affecting infracommunity structure (abundance and prevalence of infection) and measures of component community structure were analyzed.

CONCLUSIONS

Since at least two species of rat borne helminths in Kuala Lumpur have the potential to infect humans, and these showed high prevalences in the rats, the assessment and regular monitoring of infections carried by wild rodents have important roles to play in public health.

Parasite fauna of introduced pumpkinseed fish Lepomis gibbosus: first British record of Onchocleidus dispar (Monogenea)

A survey of pumpkinseed Lepomis gibbosus from a stillwater fishery in southern England revealed infections by the ancyrocephalid monogenean Onchocleidus dispar at 100% prevalence. Host specificity of O. dispar to North American centrarchid fish suggests that it is a non-native parasite, introduced to Britain with L. gibbosus. Mean intensity of O. dispar was significantly higher in male (25.5 parasites) compared to female (15) and immature (7) hosts, but was not influenced by host standard length or sampling time. This sex-biased parasitism is likely to be related to both ecological and physiological factors, such as differential exposure to infective stages during nest building, or higher susceptibility to infection due to enhanced host stress levels. O. dispar significantly dominated the external surfaces and the outer gill arches. Analysis of the spatial distribution of the parasite between the 9 regions of gill surface determined that as density increased, higher numbers of parasites were found on the anterior and central gill regions compared to posterior (distal) regions. Apparent microhabitat selection is discussed in terms O. dispar life cycle, maximising oxygen availability, avoiding unstable areas and increasing intraspecific contact. The absence of O. dispar in the gills of roach, rudd and gudgeon sampled from the same fishery supports the assumption that this parasite is currently of little threat to native fish populations.

Prevalence of anthelmintic resistance on 62 beef cattle farms in the North Island of New Zealand

AIM

To establish the prevalence of anthelmintic resistance in parasitic nematodes on a random sample of beef cattle herds in the North Island of New Zealand.

METHODS

A cross-sectional prevalence study was conducted using a standardised faecal nematode egg count (FEC) reduction (FECR) test (FECRT) for ivermectin, levamisole and albendazole on 60 calves on each of 62 farms in the North Island chosen at random from farms that conformed with the selection criteria. Resistance to an anthelmintic was inferred when there was <95% reduction in FEC 7-10 days after treatment. Larval cultures were performed for all control groups and for treated groups for which resistance was evident.

RESULTS

Of the farms that completed the FECRT, 4/61 (7%) showed > or =95% reduction in FEC for all anthelmintics tested. Resistance to ivermectin was evident on 56/61 (92%) farms, to albendazole on 47/62 (76%) farms, and to both ivermectin and albendazole on 45/61 (74%) farms. Resistance to levamisole was evident on only 4/62 (6%) farms. The parasites most prevalent in resistant populations cultured were Cooperia spp. On 45/61 (74%) farms where Cooperia spp were present in sufficient numbers, resistance to both ivermectin and albendazole was evident. No cases of levamisole-resistant Cooperia spp were detected. Resistance of Ostertagia spp to ivermectin was evident on 4/45 (9%) farms, to albendazole on 15/46 (35%) farms, and to levamisole on 4/46 (9%) farms.

CONCLUSION

Anthelmintic resistance in parasitic nematodes of cattle is common in the North Island of New Zealand. Beef farmers need to be aware of the risks posed by anthelmintic resistance, and routine FECR testing is recommended to ensure optimal productivity and to guide decision-making when purchasing anthelmintics to be used on-farm.

Occurrence of gastrointestinal helminths in Bactrian camel in Iran

A study on naturally acquired gastrointestinal helminthic parasites in Bactrian camel was carried out in Ardabil province, northwest of Iran, which is the main site of this species in Iran. This species has importance in Iran due to its low population. A total of 25 faecal samples (25% of population) were examined by Clayton Lane method to determine the egg count of different types of helminths in different age groups. Helminth eggs were found in 13 (52%) of the faecal samples (0-191 eggs/gm, 51.96±13.82). Bactrian camels were infected with Nematodirus sp. (32%), Trichuris sp. (32%), Marshallagia sp. (28%), Moniezia sp. (28%) and Strongyloides sp. (16%). The age of the infected Bactrian camels was significantly higher than the non-infected camels (p<0.01) and there was a significant correlation between age and the intensity of infection (r=0.583, p=0.002). No significant difference in the ratio of the affected camels and in the intensity of infection was found between the two sexes. The results of the current study showed that helminthic infection is a serious problem in this animal in Iran.

Levels of helminthic infections in the quails Coturnix coturnix from Kingdom of Saudi Arabia

The present study aims to clarify the difference of the intensity of parasitic infection between the domestic quails Coturnis coturnis and the migrant ones. A total of 60 domesticated and 60 migratory quails were investigated during the migration season September-November 2009 for intestinal parasites. Investigations revealed that both domestic and migrant quails were susceptible to infection with three helminth parasites; a nematode (Heterakis gallinarum), and two cestodes (Choanotaenia infundibulum and Hymenolepis sp.). The prevalence of infection in the migratory males was higher than the female ones, the opposite results was obtained for the domestic birds. The differences in the prevalence were found to be statistically significant in case of the domestic birds. Single infection showed the highest prevalence followed by the double infection and finally the triple infection. The mean intensity of infection in the female domestic and migrant C. coturnix was higher than male.

Major prospects for exploring canine vector borne diseases and novel intervention methods using 'omic technologies

Canine vector-borne diseases (CVBDs) are of major socioeconomic importance worldwide. Although many studies have provided insights into CVBDs, there has been limited exploration of fundamental molecular aspects of most pathogens, their vectors, pathogen-host relationships and disease and drug resistance using advanced, 'omic technologies. The aim of the present article is to take a prospective view of the impact that next-generation, 'omics technologies could have, with an emphasis on describing the principles of transcriptomic/genomic sequencing as well as bioinformatic technologies and their implications in both fundamental and applied areas of CVBD research. Tackling key biological questions employing these technologies will provide a 'systems biology' context and could lead to radically new intervention and management strategies against CVBDs.

Gastrointestinal parasites and their prevalence in the Arabian red fox (Vulpes vulpes arabica) from the Kingdom of Saudi Arabia

The gastrointestinal parasites and prevalence of infestation in the Arabian red fox Vulpes vulpes arabica Thomas, were investigated at the King Khalid Wildlife Research Centre (KKWRC) in Thumamah, Riyadh Province, Saudi Arabia. Faecal samples were collected from 58 wild caught foxes while under anaesthesia and examined for gastrointestinal parasites stages. Male and female foxes were infected with three major groups of parasites; cestodes, nematodes, protozoa as well as an acanthocephalan. Faecal analyses revealed that 22 foxes (37.9%) were infected with two different Isospora spp. and three (5.2%) with an undescribed Eimeria sp., 12 (20.7%). Nine individuals (15.5%) harboured hookworms, (Trichosomoides sp.), two (3.5%) were infected with Trichuris sp. (probably Trichuris vulpes) and one individual (1.7%) with Taenia sp. (probably Taenia hydatigena). Carcasses of five male and three female foxes were necropsied. Four of the necropsied carcasses yielded Ancylostoma caninum, two each harboured Pterygodermatitis affinis, T. vulpes and Macracanthorhynchus catalinus, in six foxes Joyeuxiella echinorynchoides was found. Five and four foxes were infected with T. hydatigena and Diplopylidium nölleri, respectively. The possible role of the Arabian red fox as an intercalary host essential for the life cycle of Trichosomoides sp., common to the Libyan jird, Meriones libycus, in particular and the importance of this species as a vector for zoonotic infections and in the spread of other parasites to wild and domestic animals in general is discussed.

Chronic exposure and decontamination of a marine sculpin (Myoxocephalus scorpius) to polychlorinated biphenyls using selected body indices, blood values, histopathology, and parasites as bioindicators

This study was conducted to assess the health of a subtidal marine sculpin, Myoxocephalus scorpius, naturally exposed in a shipping terminal where polychlorinated biphenyls (PCBs) had been spilled, as well as that of others sculpins after decontamination in the laboratory for 16 weeks. Reference samples were captured at a pristine site upcurrent from the contaminated terminal. Examination of field samples caught by scuba divers showed external and toxicopathic lesions in several tissues; decreased body condition and organ indices; and decreased hemoglobin and lymphocyte levels. No difference in the diversity of parasites was observed between reference and contaminated samples, but abundance was generally greater in fish from the latter site. Although the total number of species of parasites decreased in both groups of depurated sculpins, the abundance of infections on gill and gall bladder was significantly greater in fish from the polluted site. These results suggest that M. scorpius was affected adversely by PCBs and that its responses are ecologically significant as a bioindicator species in degraded habitats. Moreover, remediation might not mitigate the observed anomalies in fish inhabiting the impacted site.

Management practices to control gastrointestinal parasites in dairy and beef goats in Minas Gerais; Brazil

Parasitic infection is recognized worldwide as a limiting factor in the production of goats, and various control methods are used to reduce economic losses, often without considering the epidemiology of the parasites. This has led to the development of highly tolerant parasite populations and the presence of chemical residues in the beef and milk. The objective of this study was to determine the level of knowledge of goat farmers about parasitic diseases and to correlate this with the epidemiology of endoparasites and parasite control practices in goat farms in the state of Minas Gerais, Brazil. The analysis was based on a questionnaire applied by trained veterinarians. The sample was homogeneous throughout the state, covering 18.4% (157/853) of municipalities. Eighty-four dairy goat farms in 81 municipalities and 200 properties with beef goats in 76 municipalities were evaluated. The herd size per goat farm ranged from 4 to 57 (average 24) for beef herds and from 2 to 308 (average 63) for dairy farms. The majority of the beef herd production was extensive and semi-extensive (98.5%), while the dairy herds were maintained under intensive farming (98.8%). The mixed production of goats and sheep was reported by 36.5% of beef goat farmers and by 20.2% of dairy goat farmers. Among the beef goats farms on which the technological level was determined, 2.0% were categorized as having high technological level, 34.5% as medium, and 63.5% as low. Of the 84 dairy farms, 30% operated at a high, 47% at a medium, and 23% at a low technological level. The adoption of practices to reduce parasitism, such as the quarantine of animals, treatment of newly arrived animals, regular cleaning of the floor, and technical assistance, was significantly higher on dairy farms than on beef farms. Although 85.7% of dairy farmers and 83% of beef farmers medicate their animals, the treatments were performed without technical criteria, and deworming intervals ranged from 30 to 120 days or more. The average interval between treatments was significantly longer in dairy goat herds (4.8 months) than in the beef herds (3.6 months). The most commonly used drugs were macrocyclic lactones (37.7% in dairy and 39.5% in beef herds) and benzimidazoles (48.9% in dairy and 31.5% in beef herds). Goat production in Minas Gerais is still in its infancy, and even though using a control program associated with other health practices, producers still rely heavily on chemicals to get satisfactory results.

Gastrointestinal helminthes in stray cats (Felis catus) from Aizawl, Mizoram, India

Gastrointestinal helminthes were collected from 27 necropsied stray cats (Felis catus) in Aizawl, Mizoram, India from January 2005 to April, 2009. The examined cats showed mixed helminthic infections, with an overall prevalence of 85.2%. Five nematodes, 2 cestodes and 1 trematode were identified. The most common helminthes were Taenia taeniaeformis (70.4%), Toxocara cati (59.3%), Physaloptera praeputalis (44.4%), Dipylidium caninum (40.7%), Spirocerca felineus (18.5%), Gnathostoma spinigerum (11.1%), Ancylostoma tubaeforme (7.4%) and Opisthorchis sp (3.7%). Co-infection with T. taeniaeformis and T. cati was seen in 48.1% (13/27), indicating the possibility of these cats were paratenic hosts for toxocariasis in cats.

Farm management practices associated with macrocyclic lactone resistance on sheep farms in New Zealand

AIM

To identify farm practices associated with the presence of resistance to a macrocyclic lactone (ML) anthelmintic on sheep farms in New Zealand.

METHODS

A cross-sectional study was conducted to test for associations between the presence of resistance to an ML anthelmintic (ivermectin) and management practices on sheep farms in New Zealand. Selection of farms was both random (n=80) and purposive (n=32; being farms with a history of suspected ML resistance). Resistance was inferred from faecal nematode egg count (FEC) reduction (FECR) tests (FECRTs) when there was <95% reduction in FEC 7-10 days after treatment with a half dose of ivermectin (0.1 mg/kg). A logistic regression model was built to identify farm-level factors that were associated with the presence or absence of ML resistance.

RESULTS

Of the 112 flock managers that were approached for interview, 103 (92%) returned useable questionnaires. The odds of ML resistance were increased: on farms that had used long-acting ML products in ewes as a pre-lambing treatment for > or =3 of the previous 5 years (odds ratio (OR) = 7.2; 95% confidence interval (CI) = 1.7-30.3); on farms where <70% of the total stock units mid-winter were from sheep (OR=6.5; 95% CI=1.6-25.6); on farms which over the year purchased >10% of the number of sheep present mid-winter (OR=7.1; 95% CI=1.5-34.7); and on farms where the average wool diameter of the main flock was <37 (OR=4.1; 95% CI=1.1-14.7) microns. The model provided a good fit to the data (pseudo R2=0.64; Hosmer-Lemeshow statistic = 0.38).

CONCLUSIONS

Explanatory factors identified as associated with the presence of ML (ivermectin) resistance on farms included the use of long-acting anthelmintic formulations in ewes pre-lambing, sources of refugia of unselected parasites on the farm, breed of sheep and their requirements for anthelmintic treatments, and the importing of resistant parasites with purchased stock. The study provides support for controls that aim to provide refugia of susceptible worms and that minimise the risk of introduction of resistance through effective quarantine drenching.

Prevalence of anthelmintic resistance on sheep farms in New Zealand

AIM

To establish the prevalence of anthelmintic resistance in parasitic nematodes on sheep farms in New Zealand.

METHODS

A cross-sectional prevalence study was conducted, using a standardised faecal nematode egg count (FEC) reduction (FECR) test (FECRT) for ivermectin, at a full (0.2 mg/kg) and half (0.1 mg/kg) dose rate, and albendazole, levamisole and albendazole-levamisole in combination, on 60 lambs (n=10 per group) on farms selected from throughout New Zealand. Farms that conformed with selection criteria were chosen at random (n=80) or with a history of suspected resistance to macrocyclic lactone (ML) anthelmintics (n=32). Resistance to an anthelmintic was inferred when there was <95% reduction in FEC 7-10 days after treatment. Larval cultures were performed for all control groups and for treated groups for which resistance was evident.

RESULTS

Of the farms randomly selected, 36% showed > or =95% FECR for all anthelmintics tested; resistance to ivermectin at 0.1 and 0.2 mg/kg liveweight was evident on 36% and 25% of these farms, respectively. Resistance to both ivermectin (0.2 mg/kg) and levamisole was evident on 8/80 (10%) farms, to ivermectin and albendazole on 10/80 (13%) farms, and to ivermectin, levamisole and albendazole on 6/80 (8%) farms. The prevalence of resistance to a half dose of ivermectin tended to be more prevalent on farms with a history of suspected ML resistance (p=0.06). Resistance to albendazole was seen across all the main parasite genera, and to levamisole in Nematodirus, Ostertagia (= Teladorsagia) and Trichostrongylus species. Resistance to ivermectin was dominated by Ostertagia spp, although Cooperia, Nematodirus and Trichostrongylus species were also implicated.

CONCLUSION

Anthelmintic resistance in parasitic nematodes of sheep is common in New Zealand. Not only was resistance to albendazole and levamisole common, but resistance to the ML, ivermectin, was at a higher prevalence than expected. Sheep farmers and advisors in New Zealand need to re-evaluate the way they manage parasites, and more research is urgently needed if the steady decline in anthelmintic susceptibility is to be halted.

Anthelmintic resistance in New Zealand: A perspective on recent findings and options for the future

A recent national survey on anthelmintic resistance in cattle and sheep in New Zealand indicated that the magnitude of the problem has increased from very low levels only a few years ago to disturbingly high levels now. There is a particular problem with multiple resistance to all three action families of anthelmintic currently available in Ostertagia (= Teladorsagia) spp in sheep, and to both macrocyclic lactones (ML) and benzimidazoles in Cooperia spp in cattle. The prevalence and extent of resistance indicate that all cattle farmers and most sheep farmers should now be using a combination anthelmintic on most occasions just to achieve effective control of all parasites. Despite this, the presence of resistant parasites has generally not been appreciated by the majority of affected farmers, possibly because most have not formally tested to determine the resistance status of nematodes on their farms. Anthelmintics will remain the cornerstone of gastrointestinal nematode control in sheep and cattle for the foreseeable future but to ensure their continued effectiveness farmers need to be constantly aware of the need to maintain adequate reservoirs of unselected nematodes, i.e. worms in refugia, to minimise the expansion of the resistant population. High-risk practices in relation to selection of resistance need to be identified and avoided or at least their use limited. These include: treating adult animals where there is no identified need, moving newly treated animals onto 'clean' pasture, and failing to effectively quarantine-drench bought-in animals. None of these are new concepts but many have not been adopted or practised. In particular, sheep farmers should endeavour to avoid treating ewes pre-lambing with long-acting anthelmintics. Farmers needs to negotiate a balance between achieving good parasite control and the sustainability of their control options.

Field studies investigating anthelmintic resistance in young cattle on five farms in New Zealand

AIM

To investigate the efficacy of pour-on anthelmintics against field strains of parasitic nematodes in young cattle on five farms in New Zealand.

METHODS

Faecal nematode egg count (FEC) reduction (FECR) tests were carried out on five calf-rearing farms using pour-on formulations of levamisole, ivermectin, eprinomectin, and the simultaneous administration of levamisole and ivermectin. Faecal samples were collected per rectum before treatment and about 7, 14, 21 and 28 days after treatment, for FEC and faecal nematode larval culture.

RESULTS

Resistance (i.e. <95% reduction in FEC) of Cooperia oncophora to ivermectin and eprinomectin was identified on all five farms. There was limited evidence of possible emerging resistance in Ostertagia spp to ivermectin but not eprinomectin, in short-tailed larvae of Cooperia spp to ivermectin and eprinomectin, and in Trichostrongylus spp to ivermectin, eprinomectin and levamisole used separately. Levamisole was effective against C. oncophora, but had variable efficacy against Ostertagia spp in the calves in this study. Simultaneous treatment with levamisole and ivermectin pour-on formulations were effective against all genera on all farms.

CONCLUSIONS

To effectively manage roundworm parasites in their calves farmers need to be aware of the resistance status of the parasites on their farms. Levamisole is likely to be an effective anthelmintic on most farms at times of the year when the impact of Ostertagia spp is not high. Simultaneous administration of levamisole and ivermectin pour-on anthelmintics to cattle is likely to control both ML-resistant C. oncophora and stages of Ostertagia spp that are not controlled by levamisole alone.

Helminth community structure of Scinax nasicus (Anura: Hylidae) from a South American subtropical area

The main goal of this study was to evaluate the relative influence of season, year of study, host body size, and host sex on abundance of helminth species parasitic in the frog Scinax nasicus. A total of 273 frogs was collected between December 2004 and November 2006 over all seasons in Corrientes City, Province of Corrientes, Argentina. Helminth community included 21 taxa, and was dominated particularly by larval trematodes. Infected frogs harboured a maximum of 7 species. Host sex and season played no significant effect in determining infracommunity parasite species abundance. Similarly, species richness was similar for both host sexes, and across time (year and season). However, occurrence of the parasites Opisthogonimus sp. 2 and Travtrema aff. stenocotyle greatly varied over time. Host body size was the main factor for determining infrapopulation structure of Centrorhynchus sp. Species richness was significantly and positively correlated with host body size. Strong associations were observed mainly between metacercariae of some species. The transmission strategies of parasites suggest that this hylid acquires infections by ingestion of infective larvae and through direct contact with larval parasites from aquatic and terrestrial habitats.

First record of Paradiplozoon amurensis (Monogenea: Diplozoidae) in Iraq from gills of the cyprinid fish Cyprinion macrostomum

A survey of gill parasites was conducted in 164 Cyprinion macrostomum (Cyprinidae) collected from the Tigris River at Tikreet city, Salah Al-Deen province, in central Iraq, in 2009-2010. The monogenean Paradiplozoon amurensis Akhmerov, 1974 (Diplozoidae) was observed in the gills of 26.2% of these fishes with a mean intensity of 2.3. This is the first report of P amurensis in Iraq. A description and morphometrics of P amurensis specimens are presented.

[Taenia martis (Cestoda, Taeniidae) from vertebrates in the Republic of Belarus]

Infestation of vertebrate animals with the cestode Taenia martis and its larvae was investigated in south-west Belarus during 2001-2008. Obligatory definitive host (common marten) and intermediate hosts (red-backed vole, yellow-necked mouse, striped field mouse, and red squirrel) of this helminth were established for the Republic of Belarus. Description and figure of the T. martis larva is given.

[Helminthes of wild birds in Bashkortostan]

Results of the helminthological dissection of 312 wild birds of 83 species from five orders were considered. Diagrams reflecting these data show the state of infestation for the orders and, separately, infestation of families in the order Passeriformes. Indices of infestation for these orders and families are also given.