Babesias of red deer (Cervus elaphus) in Ireland

ABSTRACT: Blood samples were obtained from 38 wild red deer (Cervus elaphus) at two sites in Ireland and subjected to PCR analysis of the 18S rRNA gene followed by sequencing. Two fragments of the 18S rRNA gene were generated by two different PCR protocols and subsequent sequencing suggested that at least six of the deer were infected by a babesia that, in those loci, is indistinguishable from Babesia divergens, an important tick-borne pathogen of cattle and of zoonotic significance. Additionally, a B. odocoilei-like parasite was detected in three samples and a babesia that did not match any sequences in the GenBank database was found in five samples. Neither B. capreoli nor B. venatorum (EU1) were found. There have been several reports of B. divergens occurring in deer species, including red deer, roe deer (Capreolus capreolus) and reindeer (Rangifer tarandus). However, in view of recent re-sequencing of bovine-origin samples deposited previously in GenBank, it is unlikely that any of these sequences from deer are B. divergens. The present study describes the only deer piroplasm detected so far that shows complete identity with B. divergens, in just over half of the 18S rRNA gene. The entire gene of this deer parasite should be analysed and transmission experiments undertaken before the infectivity of B. divergens for red deer can be confirmed.     

Babesia divergens (Phylum Apicomplexa) in vitro growth in the presence of calf serum

Resistance to severe babesiosis in young calves has frequently been ascribed to an unknown serum factor(s) which inhibits growth of Babesia bovis in vitro. Our experiments show that young calf sera are as suitable as adult bovine sera for the in vitro culture of Babesia divergens, indicating that in this species at least inverse age resistance is due to alternative mechanisms. The suitability of commercial foetal calf sera for B. divergens cultures seems highly variable.     

An Irish perspective on Cryptosporidium. Part 1

Cryptosporidiosis, a protozoal disease which causes significant morbidity in humans, is one of the chief causes of diarrhoea in neonatal ruminants. Although the parasite poses a significant threat to public health and animal health in Ireland, its epidemiology on the island is only poorly understood. Environmental studies have shown the waterborne parasite to be widespread in some untreated waterbodies around Ireland. The island's hydrogeological situation, combined with high stocking rates of livestock and the absence of filtration from regular water treatment, render it vulnerable to large-scale outbreaks. This review discusses the parasite in the Irish context and underlines the need for a reference facility to provide active surveillance on the island.     

Naturally occurring Trypanosoma granulosum infections in the European eel, Anguilla anguilla L. from County Mayo, western Ireland

Eels were sampled from three lake and two stream sites in the Burrishoole catchment, western Ireland, at bimonthly intervals; the eels were bled and released. Prevalence of Trypanosoma granulosum was determined using a haematocrit centrifuge technique and parasitaemia was estimated by counting trypanosomes in 30 fields (10 ocular × 10 objective) on Giemsa-stained smears. Prevalence was consistently high in eels from the lake sites, but lower and more variable in the two stream sites. Parasitaemia was generally low and the distribution highly skewed. Individual eels carrying medium and high infections were most common in late summer and autumn. The size distribution of trypanosomes found in the blood was bimodal. Seasonal changes in trypanosome morph sizes indicated that parasitaemia did not increase immediately after infection, but was delayed until water temperatures increased during the summer months.     

Changing incidence of bovine babesiosis in Ireland

Background

In Ireland bovine babesiosis is caused by the tick-borne blood parasite, Babesia divergens. A survey of veterinary practitioners and farmers in the 1980’s revealed an annual incidence of 1.7% associated with considerable economic losses. However, two subsequent surveys in the 1990’s indicated a decline in clinical babesiosis. Recent evidence from continental Europe suggests that, probably due to climate change, the distribution of the tick vector of B. divergens, Ixodes ricinus is extending to more northerly regions and higher altitudes. In addition, milder winters are thought to widen the window of tick activity.In order to determine whether any such changes have affected the incidence of bovine babesiosis in Ireland, a questionnaire survey of farmers and veterinarians was carried out and compared with data from previous surveys.

Results

Our survey indicates that while the incidence of clinical disease has continued to decline, cases can occur at any time of year. In contrast to previous surveys, affected farms were the same size as unaffected ones. There was no correlation between disease risk and the presence of deer on the land. Disease severity and mortality rates were increased because many infections were advanced by the time they were detected and treated.

Conclusion

While the precise reasons for the decline in the incidence of redwater are unknown, changes in agricultural practice are likely to be of importance. A reversal of the trend could be devastating, as vigilance among farmers and veterinarians is flagging and the national herd is losing its protective immunity to disease.     

Comparison of different methods for the solubilisation of Neospora caninum (Phylum Apicomplexa) antigen

Parasite antigens are of interest both for the development of better diagnostic tools and potential subunit vaccines. Particularly, relevant in this regard are membrane proteins as the first point of contact between host and parasite. Here, four different methods for the extraction and solubilisation of Neospora caninum proteins were evaluated by comparing protein yield, specific antigenicity and relative protein abundance in the electrophoresis profile. Extraction with SDS and sulphobetaines (SB) gave higher yields than those achieved using the standard sonication method. SDS and SB preparations also gave the best signal to noise ratio when used as capture antigens in an ELISA. Electrophoresis of the three preparations showed an even protein-banding pattern spread out over the 90-10 kDa size range. However, there were a greater proportion of lower molecular weight proteins when the sonication method was used suggesting that this method may have resulted in the degradation/proteolysis of some proteins. Extraction with Triton X-114 resulted in the concentration of three or four proteins but led to a considerable reduction in the overall protein yield. The ELISA indicated that not all of the Triton X-114 extracted proteins were involved in specific antibody binding. The optimal extraction method for parasite proteins depends on the intended application.     

An Irish perspective on Cryptosporidium. Part 2

Cryptosporidiosis, a protozoal disease which causes significant morbidity in humans, is one of the chief causes of diarrhoea in neonatal ruminants. although the parasite poses a significant threat to public health and animal health in Ireland, its epidemiology on the island is only poorly understood. Environmental studies have shown the waterborne parasite to be widespread in some untreated waterbodies around Ireland. The island's hydrogeological situation, combined with high stocking rates of livestock and the absence of filtration from regular water treatment, render it vulnerable to large-scale outbreaks. This review discusses the parasite in the Irish context and underlines the need for a reference facility to provide active surveillance on the island.     

Bulk milk ELISA and the diagnosis of parasite infections in dairy herds: a review

The bulk milk enzyme-linked immune sorbent assay (ELISA) is a rapid and inexpensive method of assessing herd exposure to pathogens that is increasingly being used for the diagnosis of parasite infections in dairy herds. In this paper, with the dairy herd health veterinarian in mind, we review the principles of the assay and the recent literature on the potential role of bulk milk ELISA for the diagnosis of ostertagiosis, fasciolosis, parasitic bronchitis due to cattle lung worm and neosporosis. It is generally accepted that assay results reflect exposure to the parasite rather than the presence of active infection. Bulk milk ELISA can be a useful tool for the veterinary practitioner as a component of a herd health monitoring programme or in the context of a herd health investigation. It can also play a role in regional or national surveillance programmes. However, the results need to be interpreted within the context of the herd-specific health management, the milk production pattern and the parasite life cycle.     

Influence of processing on quality parameters of strawberries

To determine the effects of different processing steps, such as enzymatic treatment of the mash and pasteurization, on selected quality parameters, strawberries were processed to juices and purees. To identify the processing steps causing the highest losses, samples were taken after each step, and ascorbic acid, total phenols, anthocyanins, and antioxidant capacity were analyzed. To assess the antioxidant capacity, three different methods were applied: the trolox equivalent antioxidant capacity (TEAC), the ferric reducing antioxidant power (FRAP), and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, showing correlation coefficients of 0.889 to 0.948. The antioxidant capacity decreased with processing steps except heat treatment, which partly caused an increase due to the formation of antioxidant active products. The content of ascorbic acid, in comparison to that in the frozen strawberries, decreased significantly during the processing of the fruit to puree by 77%. In the pressed cloudy juices, the loss of ascorbic acid was 37%. The decline of phenolic compounds, measured as total polyphenols and anthocyanins, was smaller (between 30-40%). Pressing and pasteurization were the most critical steps for the decrease of these compounds. The enzymatic treatment of the mash within 90 min supported the release of secondary plant metabolites, while ascorbic acid is reduced up to 20%.