Areas of Interest
Dr Barta's and his graduate students are interested in protozoan parasites of the phylum Apicomplexa. These parasites are cosmopolitan in their range of hosts infected and geographic distribution. Some are the causative agents of major diseases of humans (malaria in otherwise healthy individuals [Plasmodium spp.]; toxoplasmosis and cryptosporidiosis in the young or immunocompromised). Others are a tremendous financial burden to food producers because of the effects these parasites have on domestic animals (coccidiosis, sarcocystosis and cryptosporidiosis of livestock and poultry). All members of the phylum are parasitic. One of the most commonly encountered groups of Apicomplexa are the Coccidia. These ubiquitous parasites of vertebrates have a complex intracellular life cycle within infected intestines involving penetration by a sporozoite into a host cell, several cycles of asexual replication (merogony) forming numerous merozoites and finally a sexual cycle which produces infective stages (containing sporozoites) which pass between vertebrate hosts. Species of the genera Toxoplasma and Sarcocystis (among others) infect two or more hosts in their life cycles; Eimeria spp. only infect a single host species with few exceptions.
The long term goal of my research program is to understand the interactions which exist between parasites of the Phylum Apicomplexa (Plasmodium, Eimeria, Isospora, Toxoplasma gondii, Cryptosporidium and related organisms) and their vertebrate and invertebrate hosts at the historical, organismal and molecular levels. Currently we are examining:
- apicomplexan phylogeny in the context of host associations (host-parasite co-evolution, i.e. historical associations of populations) as well as infraspecific variation within species of coccidia infecting poultry using molecular and immunological measures of variation;
- parasite organellar cell biology and the role of organelles in host cell invasion and parasite survival (individual cell to cell associations) using sporozoites of Eimeria tenella and merozoites of a recently described apicomplexan parasite, Neospora caninum, in an in vitro system; and
- the cellular and soluble factors responsible for immunological modulation of coccidial infections during primary and secondary infections in mice and in poultry (associations between the parasite and an individual host).
- the effect that various immunization routes have on the ability of native and recombinant antigens to elicit a protective immune response in poultry.
Coccidiosis Prevention and My Flock Project
Fostering proactive coccidiosis control management in the poultry industry by developing a self-guided, interactive training module and promoting on-farm usage
A unique education program is being created to provide targeted information for coccidiosis control. Interested professionals from industry, government and academia gathered to create a self-guided, educational tool to meet the needs of large and small flock producers, hobby farmers and game bird farmers. The aim is not to replace veterinarians or company representatives, but to provide reliable and focused education. This project is funded by the Ontario Ministry of Agriculture and Food’s (OMAF) Knowledge Translation and Transfer (KTT) program, the Poultry Industry Council and members of the poultry industry.
Kayla Price is a graduate student in Dr. John Barta's lab. Dr. Barta's is a parasitologist whose main area of expertise is coccidiosis in chickens
Coccidiosis, caused by Eimeria parasites, is an “everyday” problem to the poultry industry and can impact poultry gut health and performance. Prophylactic drugs were the prevention program of choice; however, resistance and drug-residues concerns may limit future use. Unfortunately, stopping prophylactic drug use will put commercial poultry at risk for coccidiosis outbreaks and alternate methods, such as vaccination, are becoming the main replacement. However, vaccination requires the end-user (e.g. producer) to have knowledge of the parasite to achieve the method’s full potential but the intricacies of parasite management can be perceived as complex by the end-user. In-person training by vaccine companies is expensive and labour intensive and is thus not practical.
This project will provide a novel, self-guided educational tool for poultry workers who have direct involvement with Eimeria management, whether in the hatchery or in the barn. First, in consultation with the poultry industry, especially Ontario workers, best practices will be established. Following these consultations, the tool will be assembled by students with interest in poultry health and welfare and with input and feedback from producers. By tapping the knowledge and expertise of researchers, students and industry partners, this KTT project will foster enhanced understanding of the parasite and best practices to initiate proactive Eimeria management by the end-users.
- Control of the reproductive axis: Balancing act between stimulatory and inhibitory inputs.
- From the Macro to the Micro: Gel Mapping to Differentiate between Sporozoites of Two Immu-nologically Distinct Strains of Eimeria maxima (Strains M6 and Guelph).
- Molecular phylogenetics of eimeriid coccidia (Eimeriidae, Eimeriorina, Apicomplexa, Alveolata): A preliminary multi-gene and multi-genome approach.
- A linear mitochondrial genome of Cyclospora cayetanensis (Eimeriidae, Eucoccidiorida, Coc-cidiasina, Apicomplexa) suggests the ancestral start position within mitochondrial genomes of eimeriid coccidia.
- Simultaneous identification and DNA barcoding of six Eimeria species infecting turkeys using PCR primers targeting the mitochondrial cytochrome c oxidase subunit I (mtCOI) locus
- Shedding of live Eimeria vaccine progeny is delayed in chicks with delayed access to feed after vaccination
- Complete mitochondrial genome sequences from five Eimeria species (Apicomplexa; Coccidia; Eimeriidae) infecting domestic turkeys
- Description of two new Isospora species causing visceral coccidiosis in captive superb glossy starlings, Lamprotornis superbus (Aves: Sturnidae)
- The complete mitochondrial genome sequence of Hepatozoon catesbianae (Apicomplexa: Coc-cidia: Adeleorina), a blood parasite of the green frog, Lithobates (formerly Rana) clamitans
- Re-description of a genetically typed, single oocyst line of the turkey coccidium, Eimeria adenoeides Moore and Brown, 1951
- Divergent nuclear 18S rDNA paralogs in a turkey coccidium, Eimeria meleagrimitis, complicate molecular systematics and identification.
- Examination of a novel practical poultry management method to enhance the effect of live Eimeria vaccination for conventionally housed replacement layer pullets.