PREVALENCE AND MOLECULAR IDENTIFICATION OF Cryptosporidium spp. IN LAMBS ON THE HUASTECA ALTA REGION, STATE OF VERACRUZ, MÉXICO
Cryptosporidium is a protozoan parasite that causes enteric infection in several mammalian species, including humans. This infection has a major impact in immunocompromised domestic mammals and public health because the parasite oocysts are resistant to environment and can contaminate food and water. In sheep, cryptosporidiosis is presented with mild to severe yellowish diarrhea, plus weight loss, depression, abdominal pain, and eventually the animal may die; usually, it is more common in lambs 1-30 days old. Therefore, the objective of this study was to determine the prevalence of Cryptosporidium spp., and identify the species of the oocysts in lambs maintained in extensive grazing systems at the Huasteca Alta region, State of Veracruz, Mexico. From March to June 2012, two hundred and ten fecal samples were collected from Blackbelly x Pelibuey lambs 7-21 days old, from 21 flocks located in seven locations at the Huasteca Alta region. The samples were processed by performing a fecal smear and then dyed by the Kinyoun acid-alcohol resistant staining, and then were observed with a microscope (LCD Digital Leica) at 100 X. A molecular diagnosis was performed using nested PCR to amplify the region of the 18S rRNA gene of the parasite (830 bp), and the positive samples were sequenced. The overall prevalence of Cryptosporidium spp. infection in lambs was 19.5%: 10.5 % in 7-14 days old, and 9% in 15-21 days old. The prevalence in flocks ranged from 10 to 40%, and in 62% of them there was at least one infected lamb. In the seven locations positive lambs were detected, and the highest prevalence was observed in Tamiahua (36.67 %). The sequenced samples had a homology between 96 to 100% with the 18S rRNA region of C. parvum. This is the first report of the presence of C. parvumin lambs in the Mexican tropic.
Keywords: Cryptosporidium, sheep, genotyping.