ABSTRACT
No study in the past has examined the genetic diversity and zoonotic potential of Giardia duodenalis in dairy cattle in India. To assess the importance of these animals as a source of human G. duodenalis infections and determine the epidemiology of bovine giardiasis in India, fecal samples from 180 calves, heifers and adults and 51 dairy farm workers on two dairy farms in West Bengal, India were genotyped by PCR-RFLP analysis of the ß-giardin gene of G. duodenalis followed by DNA sequencing of the nested PCR products. The overall prevalence of G. duodenalis in cattle was 12.2% (22/180), the infection being more prevalent in younger calves than in adult cattle. Zoonotic G. duodenalis Assemblage A1 was identified in both calves and workers although the most prevalent genotype detected in cattle was a novel Assemblage E subgenotype. These findings clearly suggest that there is a potential risk of zoonotic transmission of G. duodenalis infections between cattle and humans on dairy farms in India.
Subject(s)
Cattle Diseases/parasitology , Giardia/isolation & purification , Giardiasis/veterinary , Zoonoses/parasitology , Animals , Base Sequence , Cattle , Cattle Diseases/transmission , DNA, Protozoan/chemistry , DNA, Protozoan/genetics , Feces/parasitology , Female , Genetic Variation , Giardia/genetics , Giardiasis/parasitology , Giardiasis/transmission , Humans , India , Molecular Sequence Data , Phylogeny , Polymerase Chain Reaction/veterinary , Polymorphism, Restriction Fragment Length , Sequence Alignment , Zoonoses/transmissionABSTRACT
Few studies in the past have examined the genetic diversity and zoonotic potential of Cryptosporidium in dairy cattle in India. To assess the importance of these animals as a source of human Cryptosporidium infections, fecal samples from 180 calves, heifers and adults and 51 farm workers on two dairy farms in West Bengal, India were genotyped by PCR-RFLP analysis of the 18S rRNA gene of Cryptosporidium followed by DNA sequencing of the PCR products. Phylogenetic analysis was carried out on the DNA sequences obtained in the study and those available in GenBank. The overall prevalence of Cryptosporidium in cattle was 11.7% though the infection was more prevalent in younger calves than in adult cattle. The occurrence of Cryptosporidium parvum, Cryptosporidium bovis, Cryptosporidium ryanae and Cryptosporidium andersoni in cattle followed an age-related pattern. A Cryptosporidium suis-like genotype was also detected in a calf. Farm workers were infected with Cryptosporidium hominis, C. parvum and a novel C. bovis genotype. These findings clearly suggest that there is a potential risk of zoonotic transmission of Cryptosporidium infections between cattle and humans on dairy farms in India.
Subject(s)
Cattle Diseases/parasitology , Cryptosporidiosis/veterinary , Cryptosporidium/isolation & purification , Intestinal Diseases, Parasitic/veterinary , Phylogeny , Zoonoses/parasitology , Agriculture , Animals , Base Sequence , Cattle , Cattle Diseases/epidemiology , Cattle Diseases/transmission , Cryptosporidiosis/epidemiology , Cryptosporidiosis/parasitology , Cryptosporidiosis/transmission , Cryptosporidium/genetics , DNA, Protozoan/chemistry , DNA, Protozoan/genetics , Feces/parasitology , Female , Humans , India/epidemiology , Intestinal Diseases, Parasitic/epidemiology , Intestinal Diseases, Parasitic/parasitology , Intestinal Diseases, Parasitic/transmission , Molecular Sequence Data , Polymerase Chain Reaction/veterinary , Polymorphism, Restriction Fragment Length , RNA, Ribosomal, 18S/chemistry , RNA, Ribosomal, 18S/genetics , Sequence Alignment , Sequence Analysis, DNA , Zoonoses/epidemiology , Zoonoses/transmissionABSTRACT
The significance of Cryptosporidium as a causative agent of diarrhea has been assessed in bovine for a period of 2 years. A total of 940 faecal samples (470 samples in each year) both from diarrhoeic and non-diarrhoeic bovine (0-12 months age) were examined during three different seasons (rainy season, summer and winter). Overall Cryptosporidium was detected in 17.46% and 18.04% cases in first and second year, respectively. Out of 50.21% diarrhoeic and 49.79% non-diarrhoeic cases Cryptosporidium was detected in 26.79% and 8.13% in first year and 27.49% and 8.59% in second year. Year did not have any significant effect on the occurrence of cryptosporidiosis in bovine during this study period. The prevalence of cryptosporidiosis, both in diarrhoeic (61.64%) and non-diarrhoeic (47.22%) cases was highest in 0-1-month age group (P<0.01). Such a high percentage of cryptosporidiosis in clinically asymptomatic animals indicated that the particular age group of animals might be reservoir for the parasite. During this study period highest prevalence was recorded in rainy season (27.55%) followed by summer (16.99%) and winter (8.71%) (P<0.01). A total of 166 positive cases were genotyped. Molecular characterization of bovine cryptosporidiosis has been carried out by PCR-RFLP analysis of SSU rRNA gene and results indicated that Cryptosporidium parvum mainly responsible for diarrhea in bovine in India.
