Journal Article

CRYPTOSPORIDIUM BOVIS N. SP. (APICOMPLEXA: CRYPTOSPORIDIIDAE) IN CATTLE (BOS TAURUS)

Fayer, Ronald, Santín, Mónica, Xiao, Lihua

2005

Overview

A new species of Cryptosporidium, C. bovis, is described. Oocysts of C. bovis, previously identified as Cryptosporidium genotype Bovine B (GenBank AY120911), are morphologically indistinguishable from those of C. parvum. They are excreted fully sporulated and contain 4 sporozoites, but lack sporocysts. Oocysts measure 4.76–5.35 μm (mean = 4.89 μm) × 4.17–4.76 μm (mean = 4.63 μm), with a length-to-width ratio of 1.06 (n = 50). Oocysts were not infectious for neonatal BALB/ c mice, but were infectious for 2 calves that were previously infected with C. parvum. Oocysts were not infectious for 2 experimentally exposed lambs less than 1 wk of age and were not detected in 42 lambs 2–3 mo of age, but were detected in a 2-wk-old lamb. In an earlier study, 79 of 840 calves on 14 dairy farms in 7 states were found infected with the new species. Most calves were 2–7 mo of age and none exhibited signs of diarrhea. This new species has been found in 10 of 162 calves aged 9 to 11 mo on a beef farm in Maryland. Fragments of the 18S rDNA, HSP-70, and actin genes were amplified by PCR, and purified PCR products were sequenced. Multilocus analysis of the 3 unlinked loci demonstrated the new species to be distinct from C. parvum and also demonstrated a lack of recombination, providing further evidence of species status. Based on these biological and molecular data, we consider this highly prevalent Cryptosporidium that infects primarily postweaned calves to be a new species and propose the name Cryptosporidium bovis n. sp. for this parasite.

• Publisher: American Society of Parasitologists,Allen Press Inc
• Subject: Actin / actin gene / Actins / Actins - genetics / Age / Animals / Animals, Newborn / Beef cattle / Biological and medical sciences / Bos taurus / Calves / Cattle / Cattle Diseases / Cattle Diseases - parasitology / Cattle Diseases - transmission / chemistry / classification / cryptosporidiosis / Cryptosporidiosis - parasitology / Cryptosporidiosis - transmission / Cryptosporidiosis - veterinary / Cryptosporidium / Cryptosporidium - classification / Cryptosporidium - genetics / Cryptosporidium - pathogenicity / Dairy farming / Dairy farms / Diarrhea / disease prevalence / DNA, Protozoan / DNA, Protozoan - chemistry / DNA, Protozoan - isolation & purification / DNA, Ribosomal / DNA, Ribosomal - chemistry / DNA, Ribosomal - isolation & purification / Farms / Feces / Feces - parasitology / Fundamental and applied biological sciences. Psychology / General aspects / General aspects and techniques. Study of several systematic groups. Models / Genes / genetics / Genotype & phenotype / Genotypes / host range / HSP-70 gene / HSP70 Heat-Shock Proteins / HSP70 Heat-Shock Proteins - genetics / Humans / infection / Infections / Invertebrates / isolation & purification / Lamb / Lambs / Male / Mammalia / Mice / Mice, Inbred BALB C / Microscopy / molecular systematics / Neonates / New species / nucleotide sequences / Oocysts / Oocysts - ultrastructure / Parasites / Parasitology / pathogen identification / pathogenicity / Phylogenetics / Phylogeny / Polymerase Chain Reaction / Polymerase Chain Reaction - veterinary / Recombination / ribosomal DNA / RNA, Ribosomal, 18S / RNA, Ribosomal, 18S - genetics / Sheep / Sporocysts / Sporozoites / SYSTEMATICS-PHYLOGENETICS / taxonomy / transmission / ultrastructure / Ungulates / Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution / veterinary