Dr Barta 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 his 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.
- 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.