E. Papadopoulos

On a Cercopithifilaria sp. transmitted by Rhipicephalus sanguineus: a neglected, but widespread filarioid of dogs

BackgroundThis study was aimed at investigating the distribution of a Cercopithifilaria sp. sensu Otranto et al., 2011 with dermal microfilariae recently identified in a dog from Sicily (Italy). A large epidemiological survey was conducted by examining skin samples (n = 917) and ticks (n = 890) collected from dogs at different time points in Italy, central Spain and eastern Greece.ResultsThe overall prevalence of Cercopithifilaria sp. in the sampled animal populations was 13.9% and 10.5% by microscopy of skin sediments and by PCR on skin samples, respectively. Up to 21.6% and 45.5% of dogs in Spain were positive by microscopical examination and by PCR. Cumulative incidence rates ranging from 7.7% to 13.9% were estimated in dogs from two sites in Italy. A low level of agreement between the two diagnostic tests (microscopical examination and PCR) was recorded in sites where samples were processed in parallel. Infestation rate as determined by tick dissection (from 5.2% to 16.7%) was higher than that detected by PCR (from 0% to 3.9%); tick infestation was significantly associated with Cercopithifilaria sp. infestation in dogs from two out of four sites. Developing larvae found in ticks were morphometrically studied and as many as 1469 larvae were found in a single tick.ConclusionsOur data suggest that, in addition to the most common species of filarioids known to infest dogs (i.e., Dirofilaria immitis, Dirofilaria repens and Acanthocheilonema reconditum), Cercopithifilaria sp. with dermal microfilariae should be considered due to its widespread distribution in southern Europe and high frequency in tick-exposed dogs.

The role of targeted selective treatments in the development of refugia-based approaches to the control of gastrointestinal nematodes of small ruminants

Anthelmintic resistance is recognised as a major problem affecting small ruminant production worldwide and now threatens the sustainability of many of these systems. One method that has been proposed to prolong the efficacy of our current anthelmintics is the maintenance of a parasite population in refugia (unexposed to a drug) which will maintain the genes for susceptibility within the parasite population. Management strategies that employ refugia-based methods include targeted or strategically timed whole flock treatments, targeted selective treatments (TST), whereby only a proportion of the flock is treated at any one time, and the dilution of resistant with susceptible parasites. The ability to effectively target anthelmintic use relies on the identification of those animals that will most benefit from treatment. This review explains the concept of refugia, describes the role of refugia-based approaches to the management of anthelmintic resistance and reviews the markers that have been studied as indicators for TSTs as well as the implementation of refugia-based strategies. Recent results suggest that targeting anthelmintic treatment on the basis of anaemia, milk production and liveweight gain may offer a means of reducing anthelmintic usage whilst still maintaining animal performance.

Anthelmintic resistance in sheep in Europe: A selected review

Intensive use of anthelmintics to control gastrointestinal nematodes selects for anthelmintic resistance, which has become an important issue in many European countries. Presence of nematode strains resistant to benzimidazoles, imidazothiazoles and/or macrocyclic lactones has been repeatedly reported, particularly for the three most important genera, Haemonchus, Teladorsagia and Trichostrongylus. Additionally, multiple drug-resistant populations of these parasites have also been detected. Examples are given for the situation in European countries with differing climatic conditions and management systems of small ruminants. The widespread emergence of multi-resistant nematodes proves that the past intensive suppressive chemical control strategies may not be a successful approach any longer. Experience from the up to now development of anthelmintic resistance suggests that modern control schemes should not rely on sole use of anthelmintics, but employ other, more complex and sustainable recipes, combing chemical, environmental and immunological control.

Drought and flock isolation may enhance the development of anthelmintic resistance in nematodes

A survey of anthelmintic resistant nematodes was conducted in sheep and goat flocks in Greece using in vivo and in vitro tests. Faecal egg count reduction tests in Macedonia were all greater than 99% indicating very high sensitivity of the nematodes to anthelmintics. In vitro tests showed benzimidazole resistant Teladorsagia circumcincta in 17 out of 106 flocks on small islands. On the mainland there were only three cases of benzimidazole resistance out of 310 flocks and animals had recently been introduced to the flocks. Flocks on the islands are isolated and there are higher temperatures than on the more mountainous mainland, where flocks tend to intermingle. It is concluded that drought and isolation are likely to be the major factors accounting for the development of anthelmintic resistance in nematodes in the island flocks.

Standardization of the egg hatch test for the detection of benzimidazole resistance in parasitic nematodes.

The ability to reliably detect anthelmintic resistance is a crucial part of resistance management. If data between countries are to be compared, the same test should give the same results in each laboratory. As the egg hatch test for benzimidazole resistance is used for both research and surveys, the ability of different laboratories to obtain similar results was studied through testing of known isolates of cyathostomins, Haemonchus contortus, Ostertagia ostertagi, and Cooperia oncophora in programs supported by the EU (Cost B16 and FP6-PARASOL). Initial results showed difficulties in obtaining reproducible and similar data within and between laboratories. A series of ring tests, i.e., simultaneous and coordinated rounds of testing of nematode isolates in different laboratories was subsequently performed. By adopting identical protocols, especially the use of deionized water and making dilutions of thiabendazole in dimethyl sulfoxide in the final ring test, laboratories correctly identified both susceptible and resistant isolates. The protocols for the test and preparation of solutions of thiabendazole are described.

Health management of ewes during pregnancy

The objectives of health management of ewes during pregnancy are as follows: (i) successful completion of pregnancy at term, (ii) birth of healthy and viable lambs, with optimal birth and potential weaning bodyweight, (iii) optimum milk production during the subsequent lactation and (iv) improved management in relation to drug residues in animal products. Knowledge of the physiological background of pregnancy in ewes: changes, mechanisms and interactions, during pregnancy is important for the overall health management of ewes during pregnancy. Health management of pregnant ewes includes diagnosis of pregnancy and evaluation of the number of foetuses borne, which will support strategies for subsequent management of the flock. Nutritional management of ewes depends upon the stage of lactation and specifically aims to (i) prevention of pregnancy toxaemia and other metabolic diseases during the peri-partum period, (ii) formation of colostrum in appropriate quantity and quality, (iii) production of lambs with normal future birth bodyweight and (iv) support of increased milk yield during the subsequent lactation. At the end of lactation, udder management of pregnant ewes includes its clinical examination, culling of ewes considered unsuitable for lactation and, possibly, the intramammary administration of antibiotics; objectives of that procedure are (i) to cure infections which have occurred during the previous lactation and (ii) to prevent development of new mammary infection during the dry period. Management of abortions includes the correct and timely diagnosis of the causative agent of the disorder, as well as the strategic administrations of chemotherapeutic agents, aiming to prevent abortions in flocks with confirmed infection with an abortifacient agent, especially if no appropriate vaccinations had been carried out before the mating season. During the final stage of pregnancy, health management of ewes includes administration of appropriate anthelmintic drugs, aiming to eliminate gastrointestinal helminthes (thus, increasing production output of ewes) and preventing the built-up of parasitic burdens in the environment (thus, reducing infection of lambs during their neonatal period). Vaccinations of pregnant ewes aim to protect these animals, as well as their offspring, especially against diseases which are a frequent cause of neonatal mortality (e.g., clostridial infections). Health management also aims to prevent the main metabolic disorders of pregnant ewes (i.e., pregnancy toxaemia and hypocalcaemia), as well as to monitor flocks for development of these disorders. Health management of pregnant ewes is completed with application of husbandry practices before the start of the lambing season. Finally, in some cases, health management may include induction and synchronisation of lambings, which is a management or therapeutic procedure.

Seroprevalence of equine piroplasms and host-related factors associated with infection in Greece.

Serum samples were collected from a total of 544 equids that included 524 horses, 13 mules, and 7 ponies from various regions of mainland Greece and were examined by competitive-inhibition ELISA (cELISA) to evaluate the level of exposure of Greek equids to Theileria (Babesia) equi and/or Babesia caballi, the causative agents of piroplasmosis. Association between seropositivity and host-related factors of species, gender, age, origin, activity and location were investigated. The overall seroprevalence was 11.6% (9.1-14.6%) with 95% confidence limit. The seroprevalence for T. equi and B. caballi was found to be 11% (8.6-14%) and 2.2% (1.2-3.9%), respectively. The animal-related factors significantly linked with seropositivity were the species, activities of farming, racing, recreation, and geographic location in Attica, Macedonia, Peloponnese and Thessaly region (p<0.05). The relative risks for the presence of T. equi, B. caballi and mixed infection in mules compared to horses was 8.39, 33.58 and 40.31, respectively. The infection level for T. equi, B. caballi and mixed infection were significantly higher in farm equids than in racing equids (p<0.05). Also, the rate of infection of T. equi was higher in farm equids than recreational equids (p<0.05). The relative risk of T. equi infection between farming equids and equids used only for recreation activity was 3.25-1, while the relative risk of B. caballi infection was 0.14-1 for racing animals relative to recreation animals. The region with the highest level of infection to both parasites was Thessaly (38.8% T. equi and 6.1% B. caballi), followed by Peloponnese (10.4% T. equi and 3.9% B. caballi), Attica region (8.3% T. equi and 0.6% B. caballi) and finally Macedonia the region with the lowest prevalence (6.6% T. equi and 4.4% B. caballi). A higher seroprevalence rate was found among local animals compared to imported equids, indicating that equine piroplasm infection is enzootic in Greece. T. equi seroprevalence was significantly different and higher among increasing age groups of equids, suggesting persistent infections or lower transmission levels whereby animals may need to be exposed longer before acquiring the infection. Competent tick vectors Rhipicephalus bursa and Rhipicephalus sanguineus for the transmission of equine piroplasmosis were recovered from horses and dogs, respectively.

Assessment of dietary supplementation with probiotics on performance, intestinal morphology and microflora of chickens infected with Eimeria tenella

We evaluated the effects of dietary supplementation with different preparations of probiotics on the performance of broiler chickens experimentally infected with 2 × 10(4) sporulated oocysts of Eimeria tenella at 14 days of age. Three hundred, day-old, Cobb-500 chicks, as hatched, were separated into 10 equal groups with three replicates. Two of the groups, one challenged with E. tenella oocysts and the other not, were given a basal diet and served as controls without medication. The other challenged groups were given the anticoccidial lasalocid (60 mg/kg) or Enterococcus faecium (5 × 10(8) or 5 × 10(9)cfu/kg feed), Bifidobacterium animalis (5 × 10(8)cfu/kg feed), Lactobacillus reuteri (5 × 10(8)cfu/kg feed), Bacillus subtilis (5 × 10(8)cfu/kg feed), or a multi-species probiotic mix at 5 × 10(8) or 5 × 10(9)cfu/kg feed, respectively. The trial lasted 6 weeks. Individual body weight, feed intake per pen and feed conversion ratio values were recorded weekly, along with the extent of bloody diarrhea, excreta oocyst numbers and bird mortality. Caecal lesions were assessed and intestinal samples were taken for histopathological and bacteriological evaluation from ileum and caecum. Overall growth performance of chickens fed the multi-species probiotic mix at both levels was higher (P<0.05) compared to the infected control. Overall oocyst shedding was lowest (P<0.05) in the lasalocid supplemented group. Villous height was higher (P<0.05) in Bacillus supplemented groups compared to infected controls. The Lactobacillus supplemented group had the highest (P<0.05) numbers of both Lactobacillus and Bifidobacterium in ileum and caecum. In conclusion, dietary probiotics are promising for further investigation on improving intestinal health and growth performance of broiler chickens experimentally challenged with E. tenella.

The use of targeted selective treatments against gastrointestinal nematodes in milking sheep and goats in Greece based on parasitological and performance criteria

This study compared the use of targeted selective treatment (TST) with systematic whole-flock treatments in 38 dairy sheep and goat farms in Greece. Criteria for individual treatments were either parasitological (nematode faecal egg count) or performance-based (body condition score or milk yield). The possible effect of treatment on resistance to benzimidazole anthelmintics was assessed using the Egg Hatch Test. Mean faecal egg counts decreased during the 12-month experimental period in all groups, and were lowest in the TST group treated according to faecal egg count (P<0.05). The number of sheep and goats treated by TST was reduced compared with systematic treatments. Mean thiabendazole-egg death dose(50) (TBZ-ED(50)) values from all groups were similar at the beginning and end of the study (P>0.05), but significant variation in TBZ-ED(50) was noted over the study period in systematically treated goats (P=0.045). Third stage larvae belonging to the genera Teladorsagia, Trichostrongylus and Haemonchus were dominant throughout the experimental period in all flocks. It was concluded that the use of targeted selective treatment reduced the number of anthelmintic treatments to achieve a similar level of parasite control or animal production and may offer a viable option to combine animal production with effective parasite control in Greece.

Efficacy of moxidectin against sarcoptic mange and effects on milk yield of ewes and growth of lambs.

Forty-eight dairy ewes and 45 lambs naturally infested with sarcoptic mange, were divided into three equal groups and treated with moxidectin 1% inj. sol. at a dose rate of 0.2 mg moxidectin kg(-1) bodyweight once or twice ten days apart. During the study, the skin lesions were scored and the number of mites recovered in facial skin scrapings from the animals were recorded. Moxidectin was found to be effective against ovine sarcoptic mange, when given twice; the percentage reduction of mites was 100% (p < 0.0001) and the skin lesions disappeared completely (p = 0.0001). In sheep treated once only, the percentage reduction of mites varied from 75% to 92%. Treated ewes produced up to 22.4% more milk than the infested ones (p = 0.0001). Treated lambs had up to 15% greater final weight and up to 23.7% more growth than infested controls (p = 0.0001). It is concluded that two injections of moxidectin 1% inj. sol. at a dose rate of 0.2 mg kg(-1) bodyweight, given ten days apart, were effective against ovine sarcoptic mange. Furthermore, it is considered that sarcoptic mange adversely affects the production of the infested animals.