Host adaptation and host-parasite co-evolution in Cryptosporidium: implications for taxonomy and public health.
To assess the genetic diversity and evolution of Cryptosporidium parasites, the partial ssrRNA, actin, and 70kDa heat shock protein (HSP70) genes of 15 new Cryptosporidium parasites were sequenced. Sequence data were analysed together with those previously obtained from other Cryptosporidium parasites (10 Cryptosporidium spp. and eight Cryptosporidium genotypes). Results of this multi-locus genetic characterisation indicate that host adaptation is a general phenomenon in the genus Cryptosporidium, because specific genotypes were usually associated with specific groups of animals. On the other hand, host-parasite co-evolution is also common in Cryptosporidium, as closely related hosts usually had related Cryptosporidium parasites. Results of phylogenetic analyses suggest that the Cryptosporidium parvum bovine genotype and Cryptosporidium meleagridis were originally parasites of rodents and mammals, respectively, but have subsequently expanded their host ranges to include humans. Understanding the evolution of Cryptosporidium species is important not only for clarification of the taxonomy of the parasites but also for assessment of the public health significance of Cryptosporidium parasites from animals.
Xiao
Lihua
L
Division of Parasitic Diseases, Mail Stop F-12, Centers for Disease Control and Prevention, U.S. PHS/DHHS, 4770 Buford Highway, Atlanta, GA 30341, USA. lax0@cdc.gov
Sulaiman
Irshad M
IM
Ryan
Una M
UM
Zhou
Ling
L
Atwill
Edward R
ER
Tischler
Monica L
ML
Zhang
Xichen
X
Fayer
Ronald
R
Lal
Altaf A
AA
D000199:Actins / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D003458:Cryptosporidium / Q000145:classification / Q000235:genetics* / Q000502:physiology; D016054:DNA, Protozoan / Q000235:genetics; D020459:Genes, rRNA / Q000235:genetics; D014644:Genetic Variation; D005838:Genotype; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D006790:Host-Parasite Interactions / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D011634:Public Health
D000199:Actins; D016054:DNA, Protozoan; D018840:HSP70 Heat-Shock Proteins