Whole genomic sequencing, sensitivity to anticoccidial drugs, and experimental infection in domestic chickens with pure isolates of Eimeria spp.

• Grant number: 24/19665-7
• Support Opportunities: Regular Research Grants
• Start date: October 01, 2025
• End date: September 30, 2028
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Preventive Veterinary Medicine
• Principal Investigator: Marcelo Vasconcelos Meireles
• Grantee: Marcelo Vasconcelos Meireles
• Host Institution: Faculdade de Medicina Veterinária (FMVA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil
• City of the host institution: Araçatuba
• Associated researchers: Flavia Lombardi Lopes
• Associated scholarship(s): 25/20147-3 - Determination of anticoccidial drug sensitivity of pure isolates of Eimeria lata, Eimeria nagambie and Eimeria zaria, BP.MS

Abstract

Coccidiosis is one of the most economically important diseases for the poultry industry, with an estimated annual global loss of over 3 billion dollars. Seven species of Eimeria infect domestic chickens: Eimeria acervulina, Eimeria brunetti, Eimeria mitis, Eimeria maxima, Eimeria necatrix, Eimeria praecox, and Eimeria tenella. However, the classification of three new species, Eimeria lata, Eimeria nagambie, and Eimeria zaria, was recently suggested. In Brazil, all 10 species of Eimeria have already been diagnosed; however, there is little information related to natural or experimental infections and the sensitivity to anticoccidials of E. lata, E. nagambie, and E. zaria. Furthermore, there is no information about the complete genome of the ten Eimeria species isolated in Brazil. Therefore, this study aims to: 1) obtain pure isolates of the 10 Eimeria species from domestic chickens and perform the sequencing of the complete genome of these species; 2) regarding E. lata, E. nagambie, and E. zaria, conduct an analysis of sensitivity to anticoccidial drugs and experimental infections in domestic chickens. The Eimeria spp. isolates will be derived from samples containing oocysts of various Eimeria species obtained from alternative farms in the municipalities of the interior of São Paulo. To obtain pure isolates of each species, biological characteristics such as the pre-patent period, morphological and morphometric analysis of the oocysts, and the absence of cross-immunity between different species will be used. The selected oocysts from each species will be isolated by micromanipulation and propagated in domestic chickens. The confirmation of the presence of purity of each species in the samples will be determined using species-specific PCRs. The pure oocysts of each species will be used for experimental infections and DNA extraction for genomic analysis. The analysis of the sensitivity to anticoccidial drugs most frequently used in broiler industries will be performed by inoculation of oocysts of E. lata, E. nagambie, and E. zaria in broiler chickens, analyses of the weight gain and the number of oocysts eliminated by the inoculated birds as criteria for determination of anticoccidial sensitivity. The pre-patent and patent periods, fecundity, tissue tropism, and macroscopic and microscopic lesions will be analyzed after experimental infection with each species. The complete genome of each species will be analyzed using two techniques: 1) short reads analysis, using Illumina technology; 2) long reads analysis, using PacBio technology. (AU)