Intra-Species Diversity and Panmictic Structure of Cryptosporidium parvum Populations in Cattle Farms in Northern Spain

• Published in: PloS one Vol. 11; no. 2; p. e0148811
• Main Authors: Ramo, Ana, Quílez, Joaquín, Monteagudo, Luis, Del Cacho, Emilio, Sánchez-Acedo, Caridad
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 05.02.2016; Public Library of Science (PLoS)
• Subjects: Analysis; Animals; Automation; Bayes Theorem; Bayesian analysis; Biodiversity; Biology and Life Sciences; Bovidae; Calves; Cattle; Cattle - parasitology; Cryptosporidiosis; Cryptosporidium; Cryptosporidium hominis; Cryptosporidium parvum; Cryptosporidium parvum - genetics; Cryptosporidium parvum - isolation & purification; Dairy cattle; Dairy farms; Divergence; Epidemiology; Evolutionary algorithms; Farms; Genetic aspects; Genetic diversity; Genetic Linkage; Genetic variability; Genetic Variation; Host-Parasite Interactions; Linkage analysis; Loci; Markers; Minisatellite Repeats; Pathology; People and Places; Population; Populations; Protozoa; Recombination; Research and Analysis Methods; Spain; Species diversity; Structural analysis; Studies; Weaning; Zoonoses; Spain
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0148811

The intra-herd and intra-host genetic variability of 123 Cryptosporidium parvum isolates was investigated using a multilocus fragment typing approach with eleven variable-number tandem-repeat (VNTR) loci and the GP60 gene. Isolates were collected from intensively farmed diarrheic pre-weaned calves originating from 31 dairy farms in three adjoining regions in northern Spain (País Vasco, Cantabria and Asturias). The multilocus tool demonstrated an acceptable typeability, with 104/123 samples amplifying at all twelve loci. The ML2, TP14, GP60 and the previously un-described minisatellite at locus cgd2_3850 were the most discriminatory markers, while others may be dismissed as monomorphic (MSB) or less informative (CP47, ML1 and the novel minisatellites at loci Cgd1_3670 and Cgd6_3940). The 12-satellite typing tool provided a Hunter-Gaston index (HGDI) of 0.987 (95% CI, 0.982-0.992), and differentiated a total of 70 multilocus subtypes (MLTs). The inclusion of only the four most discriminatory markers dramatically reduced the number of MLTs (n: 44) but hardly reduced the HGDI value. A total of 54 MLTs were distinctive for individual farms, indicating that cryptosporidiosis is an endemic condition on most cattle farms. However, a high rate of mixed infections was detected, suggesting frequent meiotic recombination. Namely, multiple MLTs were seen in most farms where several specimens were analyzed (90.5%), with up to 9 MLTs being found on one farm, and individual specimens with mixed populations being reported on 11/29 farms. Bayesian Structure analysis showed that over 35% of isolates had mixed ancestry and analysis of evolutionary descent using the eBURST algorithm detected a high rate (21.4%) of MLTs appearing as singletons, indicating a high degree of genetic divergence. Linkage analysis found evidence of linkage equilibrium and an overall panmictic structure within the C. parvum population in this discrete geographical area.