Dominance of Giardia assemblage B in León, Nicaragua.
Giardiasis is a major problem in León, Nicaragua, yet despite this no data are available regarding the prevalence of different Giardia genotypes in this area. To address this question, a molecular analysis of Giardia isolates from humans and dogs living in the same area in León, Nicaragua was performed. Giardia isolates from 119 Nicaraguan patients and 8 dogs were successfully genotyped using single and/or nested beta-giardin PCR with subsequent restriction length fragment polymorphism (RFLP) analysis. The analyses of human samples yielded 94 (79%) assemblage B isolates and 25 (21%) assemblage A isolates. Only the non-human-associated assemblages C and D were found in the dog samples. Sixteen isolates with assemblage A pattern, 26 isolates with assemblage B pattern and all dog isolates were further characterized by sequencing the nested beta-giardin PCR product and by molecular analyses of the glutamate dehydrogenase (gdh) gene. Within the study area the assemblage A isolates were highly genetically homogenous, showing only sub-genotypes A2 (n=3) or A3 (n=13) at the beta-giardin locus and AII only at the gdh locus while assemblage B showed a high genetic polymorphism at both loci. Seven different sub-genotypes were identified within 13 of the sequenced assemblage B beta-giardin isolates. The remaining 13 sequenced assemblage B-isolates appeared to contain several different variants of the beta-giardin gene since the chromatograms displayed one to seven double peaks. The gdh sequences showed an even higher polymorphism since only 2 of 26 assemblage B isolates were without double peaks. Two mixed infections between assemblage A and B were found when the gdh gene was analyzed. Polymorphisms were also observed in the dog-associated assemblages C and D, but to a lesser extent than in assemblage B.
Lebbad
Marianne
M
Department of Parasitology, Mycology and Environmental Microbiology, Swedish Institute for Infectious Disease Control, SE-171 82 Solna, Sweden. marianne.lebbad@smi.ki.se <marianne.lebbad@smi.ki.se>
Ankarklev
Johan
J
Tellez
Aleyda
A
Leiva
Byron
B
Andersson
Jan O
JO
Svärd
Staffan
S
D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D002675:Child, Preschool; D016172:DNA Fingerprinting; D016054:DNA, Protozoan / Q000235:genetics; D004283:Dog Diseases / Q000453:epidemiology / Q000469:parasitology*; D004285:Dogs; D005260:Female; D005872:Giardia / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D005873:Giardiasis / Q000453:epidemiology / Q000469:parasitology* / Q000662:veterinary*; D005969:Glutamate Dehydrogenase / Q000235:genetics; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D009527:Nicaragua / Q000453:epidemiology; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D015800:Protozoan Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
D016054:DNA, Protozoan; D015800:Protozoan Proteins; D005969:Glutamate Dehydrogenase