One-year parasitological screening of stray dogs and cats in County Dublin, Ireland.

To date, there are no recent studies identifying the prevalence of parasites of human and veterinary importance in dogs and cats in Ireland. The interaction between pets and wildlife species in the environment is an important source of parasite exposure to canids and felines, and one likely to be heightened in the stray animal population. This study aimed to establish the prevalence of endoparasites in unowned dogs and cats in County Dublin, Ireland. Feces from stray dogs (n = 627) and cats (n = 289) entering a rehoming centre were collected immediately after defecation. The main parasitic agents detected were ascarids (15.52 and 30.26%), Cystoisospora (3.27 and 3.69%), Giardia spp. (6.02 and 1.84%) and lungworms (0.64 and 2.08%), in dogs and cats respectively. Animals younger than 3 months of age were more likely to be infected with ascarids (P < 0.001) and Cystoisospora spp. (P = 0.008 and P = 0.014) than older animals. All lungworms were morphologically identified and dogs were infected with Angiostrongylus vasorum (0.48%) and Crenosoma vulpis (0.16%) whereas cats were only infected with Aelurostrongylus abstrusus (2.08%). This represents the first prevalence study of stray animals in Ireland. Data collected will inform the treatment and in addition, the future monitoring and control studies of parasite populations.

Bovine besnoitiosis (Besnoitia besnoiti) in an Irish dairy herd.

Bovine besnoitiosis, caused by the apicomplexan protozoan parasite Besnoitia besnoiti, was diagnosed in an Irish dairy herd. This is the first diagnosis of besnoitiosis in Ireland or the UK and the most northerly European outbreak yet described. The diagnosis occurred following a farm investigation in June 2015 into an unusual dermatological problem that had been ongoing since 2010. On an annual basis, 1-2 per cent of cows in the herd exhibited clinical signs, including skin thickening, alopecia, weight loss and poor performance. Others displayed pyrexia, limb oedema, respiratory distress and reduced milk yield. Histopathological examination of skin revealed granulomatous and eosinophilic dermatitis, with characteristic intradermal protozoal cysts, consistent with cutaneous besnoitiosis. Follow-up serological testing and clinical examination of cattle (n=228) on the farm found that 68 per cent (144/212) were seropositive for B. besnoiti In addition, 51 per cent (117/228) had characteristic scleral conjunctival cysts and 68 per cent (134/198) had vulval cysts. Postmortem examination of a severely affected animal revealed typical gross and histopathological lesions of B. besnoiti infection. These results confirmed endemic infection with B. besnoiti The identification of this exotic disease highlights the importance of veterinary surveillance at both local and national level, particularly in relation to emerging diseases.

Comparison of three methods for the detection of Angiostrongylus vasorum in the final host.

Angiostrongylosis is potentially fatal parasitic nematode infection affecting dogs which can be difficult to diagnose. In recent years several microscopical, serological and molecular detection methods have been developed, however there are few studies that have compared the relative performance of these methods. Screening necropsy material from an opportunistic sample of 140 foxes (82 of which were considered to be infected with Angiostrongylus vasorum), indicated sensitivities of 84.1% for dissection and visual examination of plucks, 69.5% for nested PCR of an 18S rRNA fragment and 76.8% for a canine A. vasorum antigen detection test (IDEXX Angio Detect) of tissue fluid samples respectively. Agreement between the tests ranged from 45.6 to 79.7%. A novel nested PCR-RFLP for the detection and identification of canid lungworm spp. is described.

Geographical distribution of Angiostrongylus vasorum in foxes (Vulpes vulpes) in the Republic of Ireland.

The reported incidence of the metastrongylid nematode Angiostrongylus vasorum, that infects dogs and other canids, is increasing worldwide outside recognized endemic foci. This apparent expansion of the parasite's range is causing concern to veterinary clinicians as the disease caused in dogs can be life threatening and its treatment is not straightforward. The red fox is thought to be a reservoir host for dogs. To investigate the spatial distribution of infection in foxes in Ireland, the hearts and lungs of 542 foxes from all over Ireland were examined. The incidence of infection was found to be 39·9% [95% confidence interval (CI) 35·7-44·1] with positive samples occurring in each of the country's 26 counties. This report confirms that the parasite is endemic in Ireland and the overall prevalence is the second highest in Europe. This is the first survey of A. vasorum infection in Irish foxes and highlights the potential exposure of the Irish dog population to high risk of cross-infection. Additionally, Crenosoma vulpis was found in seven of the foxes, a parasite not previously reported in the Irish fox.

Controlling nematodes in dairy calves using targeted selective treatments.

With increasing concerns of anthelmintic resistance in cattle nematode populations worldwide, there is a need to explore alternative approaches to nematode control. One alternative approach is the use of targeted selective treatments (TST) where only individual animals are treated instead of the entire group. This study reports the findings of a TST approach in dairy calves conducted over their first grazing season (FGS) to control both gastrointestinal nematode and lungworm challenge. Ninety-six calves with an initial mean (s.d.) age and live weight of 130 (28.3) days and 120 (23.6)kg, respectively, were randomised by breed, age and live weight to one of two treatments; Control (n=24; ×2) and TST (n=24; ×2). Control calves were treated three times at pasture with ivermectin by subcutaneous injection. Individual calves in the TST group were treated at pasture with ivermectin when one of the following thresholds was met: (1) positive for lungworm larvae using the modified Baermann technique or (2) positive or negative for lungworm larvae using the modified Baermann technique with plasma pepsinogen concentration (PP) ≥ two international units of tyrosine/litre and faecal egg count (FEC) ≥ 200 strongyle eggs per gram of faeces. Calves were rotationally grazed from July 3rd 2012 (day 0) to November 2nd 2012 (day 122) when calves were housed. Calves were weighed and sampled (blood and faecal) every three weeks. There was an effect of treatment and time on both FEC [treatment (P=0.023), time (P<0.001)] and PP [treatment (P=0.002), time (P<0.001)]. Both FEC and PP were higher in TST calves. There was a 50% reduction in anthelmintic use in TST calves compared to control calves. Clinical signs of lungworm infection, confirmed by the modified Baermann technique, were evident in TST calves on days 62 and 63 of the study. The average daily live weight gain for control and TST calves was 0.50 (0.02)kg day(-1) and 0.47 (0.03)kg day(-1), respectively (P=0.41). Thus, performance in dairy calves can potentially be maintained with fewer anthelmintic treatments but farmers need to be vigilant of the challenge posed by lungworm. Any future approach into the use of TST in FGS calves must take into consideration the relative importance of lungworm as a pathogen.

Nematode control in spring-born suckler beef calves using targeted selective anthelmintic treatments.

As anthelmintic resistance is increasingly being reported in cattle worldwide, there is a need to explore alternative approaches to gastrointestinal nematode control in cattle. A novel approach is the use of targeted selective treatments (TST) where only individual animals are treated instead of the entire group. The study objective was to determine if anthelmintic usage could be reduced using a TST-based approach in rotationally grazed first-grazing season suckler beef calves without affecting calf performance. Eighty-eight spring-born suckler beef calves, naïve to anthelmintics, with an initial mean (s.d.) age and live weight of 159 (22.4) days and 221 (42.4) kg, respectively, were used. All calves were vaccinated at pasture against dictyocaulosis at 8 and 12 weeks old. On August 9th 2013 (Week 0), when the trial began, calves were randomised by age, weight, sex, dam breed and sire breed to one of two treatments: (1) standard treatment (positive control) (n=44) and (2) TST (n=44). Samples collected one week prior to the start of the study were used as baseline covariates. Each treatment group was replicated once. All calves in the control groups were treated subcutaneously with levamisole on Week 0 and on Week 6. Individual calves in the TST groups were only eligible for treatment at pasture with the same product if predetermined thresholds were reached [plasma pepsinogen ≥ 2.0 international units of tyrosine/litre and faecal egg count ≥ 200 eggs per gram of faeces]. The trial concluded at housing on Week 13. Data were analysed using repeated measures mixed models ANOVA (PROC MIXED) (SAS 9.3). No calves in the TST groups were treated for gastrointestinal nematodes during the study period as they did not reach pre-determined treatment thresholds. Mean (sem) calf daily live weight gain for control and TST groups was 0.90 (±0.04) and 0.92 (±0.03) kg, respectively (P=0.68). Using an ELISA to detect antibodies to Dictyocaulus viviparus at Week 11, 81% of calves were seropositive. Gastrointestinal nematode challenge in spring-born suckler beef calves under these conditions can potentially be controlled with minimal anthelmintic treatments whilst not significantly impairing calf performance, provided appropriate control measures are taken to prevent dictyocaulosis from occurring.

Nailfold capillary abnormalities in sclerodermatous chronic GVHD.

Chronic GVHD (cGVHD) complicating allo-SCT commonly presents as sclerotic skin changes resembling systemic sclerosis (SSc), suggesting a common pathophysiological pathway. Damage to capillaries is considered an early event in the pathogenesis of SSc, and is associated with characteristic nailfold capillary abnormalities. Whether such nailfold capillary abnormalities occur in sclerodermatous cGVHD is unknown. Nailfold videocapillaroscopy (NVC) was used to evaluate capillary morphology, density and loop dimensions in 14 patients with sclerodermatous cGVHD, 14 sex- and age-matched SSc patients, and 14 healthy controls. It was shown that none of the cGVHD patients and controls, whereas all SSc patients showed severe capillary abnormalities. cGVHD patients and controls showed no differences in capillary density (9.05 vs 9.16 loops/mm, respectively, P=0.84), and capillary loop dimensions (total loop width 44.36 vs 45.56 µm, respectively, P=0.84). Compared with cGVHD patients, SSc patients had a reduced capillary density (9.05 vs 5.25 loops/mm, respectively, P<0.001), and an increase in capillary loop dimensions (total loop width 44.36 vs 99.97 µm, respectively, P=<0.001). In conclusion sclerodermatous cGVHD patients do not show the characteristic microvascular abnormalities seen in SSc, suggesting that capillary damage does not contribute to the pathophysiology of sclerodermatous cGVHD, and making NVC unsuitable for early identification.

Toxoplasma gondii in Ireland: seroprevalence and novel molecular detection method in sheep, pigs, deer and chickens.

Toxoplasma gondii is among the most studied parasites worldwide but there is not much information about it published in Ireland. The objectives of this study were to determine the seroprevalence of T. gondii in sheep, pigs, deer and chickens and the molecular detection of T. gondii DNA in muscle tissue. Serum samples were collected from these species at the time of slaughter at Irish abattoirs during 2007 and tested for anti-T. gondii antibodies using a commercial semi-quantitative latex agglutination test. Antibodies (titre ≥1 : 64) were found in 36% (105/292) sheep, 4.7% (15/317) pigs and 6.6% (23/348) deer. In chickens, 18% (65/364) had antibody titres, ranging between 1 : 5 and 1 : 1024. Significant (P ≤ 0.05) age-related differences in seroprevalence were found in adult sheep (58.1%) and pigs (23.1%). Significant gender differences in seroprevalence was also found in sheep with more females (43%) than males (22.4%) being positive. However, when adjusted for age through logistic regression gender was no longer significant. Seroprevalence was also evaluated on farm locations grouped to NUTS level 3, but the prevalence was too low to draw any statistical conclusions. Using a nested PCR, the presence of T. gondii DNA was detected in diaphragm samples from 3.6% (3/83) sheep, 13.0% (3/23) pig and 4.2% (3/71) deer. Meat digestion liquids from a Trichinella spp. survey in pigs were also used for the first time to detect T. gondii. Toxoplasma gondii DNA was detected in 50% (10/20) of pooled samples. This is the first in depth study of T. gondii seroprevalence in animals in Ireland and a novel method, using digestion liquid from pooled diaphragm samples, for PCR detection in pigs is described.

Advances in diagnosis of protozoan diseases.

Microscopy still remains the gold standard procedure for the diagnosis of many protozoan infections in animals, but the specific identification requires skilled and experienced personnel. Immunoassays, detecting antibodies or specific protozoan antigens, have been developed but often lack sensitivity and specificity due to close relationship between many protozoa. Recent research has focussed almost exclusively on molecular based techniques for the identification and quantification of parasite DNA in samples. Opinion differ on most appropriate targets to use and there are very few diagnostic kits available making comparison between laboratories difficult. Future research needs to focus on robust, cheap field diagnostic assays.

Longitudinal and spatial distribution of GP60 subtypes in human cryptosporidiosis cases in Ireland.

Within Europe, Ireland has one of the highest reported infection rates with the diarrhoeal protozoan pathogen Cryptosporidium. In this study 249 Cryptosporidium parvum isolates collected from Irish patients between 2000 and 2009 were subtyped by sequence analysis of the GP60 locus. A subsample of 127 isolates was also typed at the MS1 and ML1 loci. GP60 subtype IIaA18G3R1 was the predominant subtype in every year and every season throughout the country. Over the 10-year period there was no evidence that host immunity to the predominant subtype caused a shift in its prevalence. Length frequency distributions of the GP60 TCA/TCG repeats compiled from published data, showed distinct patterns for countries with predominantly zoonotic or anthroponotic transmission cycles, respectively. Although considered to be mostly affected by zoonotic cryptosporidiosis, the GP60 fragment length of Irish C. parvum isolates mirrored that of countries with predominantly human-to-human transmission, indicating more complex routes of infection between livestock and humans. Due to their homogeneity, ML1 and MS1 were not considered useful loci for subtyping C. parvum strains in Ireland.

Survival of Cryptosporidium parvum oocysts in the presence of hydrated lime.

To investigate the effects of hydrated lime on the survival of Cryptosporidium oocysts, the percentage viability of oocysts was assessed using fluorescent in situ hybridisation. In the absence of lime and with lime at a concentration of 1 per cent, there was a gradual decline in oocyst viability during the 10-day trial. Although the addition of 5 or 10 per cent lime caused the total number of oocysts to decrease, there appeared to be an increase in the proportion of potentially viable oocysts.

The comparative efficacy of four anthelmintics against a natural acquired Fasciola hepatica infection in hill sheep flock in the west of Ireland.

The aim of this study was to evaluate the efficacy of four different anthelmintics against F. hepatica in a naturally infected hill sheep flock in the west of Ireland. In a randomised trial, 138 ewes were divided into four groups. On day 0 each group was dosed with one of four anthelmintics: triclabendazole, closantel, oxyclozanide or nitroxynil. Faecal samples were obtained from each animal per rectum on the day of treatment and again at 7, 14, 21 and 56 days post-treatment. The number of F. hepatica eggs per gram of faeces was determined using the sedimentation technique and the efficacy of each anthelmintic was calculated in terms of the percentage reduction in egg count at each time point. The results for closantel, oxyclozanide and nitroxynil indicate that these drugs are effective with faecal egg count being reduced by 100% by day 14 post-treatment. However, the results for triclabendazole group yielded lower efficacy levels, with faecal egg count reductions of between 49% and 66% based on arithmetic means, over the period 7-56 days post-treatment. These results are highly indicative of triclabendazole resistant F. hepatica in sheep on this farm.

Evidence of Fasciola hepatica infection in Radix peregra and a mollusc of the family Succineidae in Ireland.

Worldwide molluscs of the genera Lymnaea, Pseudosuccinea, Galba and Stagnicola act as intermediate hosts of the common liver fluke, Fasciola hepatica. Galba truncatula is the only recorded intermediate host of F. hepatica within Ireland and is the principle intermediate host within Europe. To investigate the transmission of liver fluke on the Teagasc hill sheep farm, Co. Mayo, Ireland, snail species other than G. truncatula, were collected from the lowland pasture (snail sp. 'A') in May (n=23) and from the hill area (snail sp. 'B') in March, April and May 2008 (n=78, 53 and 36 respectively). Morphological characteristics identified snail sp. 'A' as a Succinea sp. and snail sp. 'B' as Radix peregra. PCR and subsequent sequencing of the 18S gene and internal transcribed spacer 2 (ITS-2) region of the snail rDNA were used for molecular identification. The 18S ribosomal DNA (rDNA) sequences revealed a 99% similarity with Omalonyx matheroni (Succineidae) for snail sp. 'A', and for snail sp. 'B' a 99% and 98% similarity with Radix auricularia and R. peregra, respectively. The ITS-2 sequences of snail sp. 'B' revealed a 100% similarity with R. peregra. Using PCR F. hepatica DNA was identified in 73.9% (n=17) of snail sp. 'A' collected during May and 10.3% (n=8), 60.4% (n=32) and 61.1% (n=22) of snail sp. 'B' collected during March, April and May, respectively. A priori knowledge of habitat preference and environmental tolerances of G. truncatula has failed to explain the prevalence of infection recorded in the hill sheep flock on Teagasc hill sheep farm. These findings may explain the presence of infection in sheep populations grazing hill habitats considered too acidic to maintain G. truncatula populations.

Prevalence of Cryptosporidium species in intensively farmed pigs in Ireland.

Natural Cryptosporidium infections in pigs are widespread but generally apathogenic. This study was undertaken to determine the prevalence of zoonotic Cryptosporidium spp. in piggeries in Ireland, where the drinking water supply is particularly vulnerable to contamination with zoonotic species. Overall, infections were detected in 39 out of 342 animals (11.4%), with highest infection rates among weaners (15%) and sows (13.3%). Twenty-nine positive samples were genotyped based on SSU rRNA sequence analysis. Infections with Cryptosporidium parvum, the most important zoonotic species were rare and are likely to be of greater concern to animal handlers than suppliers of drinking water. In addition to C. parvum, Cryptosporidium suis, Cryptosporidium pig genotype II, Cryptosporidium muris and a previously undescribed genotype were identified. ABI-profiles indicated the presence of different alleles in at least 40% of all genotyped isolates. This was confirmed in 3 isolates by cloning of the PCR products. Since chronic mixed infections appear to be quite common in pigs they could be considered as models for mixed infections in immunocompromised humans.